Photo by angeloangelo

I recently returned from an eight day vacation in Dubai. I never thought I would visit the Middle East in my life, so I was determined to make the most of this unique opportunity.

Every meal we had was lavish and indulgent. Every day we drank champagne and cocktails.

And although I logged over 100,000 steps during the week and made great use of the gym at our hotel, there was no denying that my clothes were uncomfortably tight when I got home.

Naturally, I regret nothing. I don’t mind how I look when I’m a few pounds heavier (most people wouldn’t notice), but I wanted to get back to my normal weight because I am more comfortable there. My clothes fit better and I feel more myself.

I’ve written before that I don’t believe in cleanses, detoxes or diets. Instead I rely on my Home Court Habits to get me back into my comfort zone.

But over the years I’ve noticed that there are certain habits I focus on more intently when I’m actively trying to lose weight.

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For The Love of Food

Welcome to Friday’s For The Love of Food, Summer Tomato’s weekly link roundup.

This week Real Food lays the smack down on diets, running won’t combat poor eating, and beer is meat’s best friend.

Want to see all my favorite links? (There’s lots more). Be sure to follow me on on Delicious. I also share links on Twitter @summertomato,  Google+ and the Summer Tomato Facebook page. I’m very active on all these sites and would love to connect with you. (And yes, I took that pepper heart pic myself).
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Organic Golden Beets

On Monday a study from scientists at Stanford made headlines by concluding that there isn’t much health value in choosing organic food over conventional food. The headline didn’t surprise me in the least, I’ve seen similar ones at least a dozen times before, but there is still so much confusion among the general public around this topic that it’s worth revisiting in the wake of this new data.

Despite what organic zealots are telling you, this wasn’t a bad study. It was a meta-analysis that examined a number of relevant health measures comparing organic versus conventionally grown foods over the last several decades. They excluded processed foods from their analysis (this is a good thing), and looked at nutrient levels as well as pesticide contamination and antibiotic resistance in both produce and animal products. They were also careful about which organic standards were included in the study. Though the analysis has plenty of limitations (all meta-analyses do), their statistics were sound and the researchers were honest about their findings. What’s really annoying is how their results were interpreted by the media.

One problem is that the word “organic” is a huge umbrella that includes sustainable, biodynamic farming practices as well as huge-scale industrial operations that barely squeeze under the “certified organic” labeling standards. As a result there is a tremendous amount of heterogeneity (a scientific word for a wide range of differences) between the organic foods being tested, as well as the types of studies that are performed. As a result, it is difficult to measure consistent differences (aka statistical significance) between organic and conventional foods in this kind of study. Unfortunately, this doesn’t do much to further our understanding of how growing practices affect health.

The huge variance among farming practices that fit under the organic umbrella is not trivial. By far the largest segment of organic products on the market could be considered industrial organic, and the farms are closer to traditional industrial farms than most of us realize. Large organic farms are typically monoculture fields just like large conventional farms, though more crop rotation is required. Industrial organic poultry and beef farms also look oddly similar to conventional industrial feedlots, even if the animals are eating organic feed. In fact, both organic and conventional industrial farms are often owned by the same mega-corporations, and share the same bottom line of profit. There’s no reason to suspect that these industrial organic foods would be markedly more nutritious than conventionally grown foods.

In contrast, smaller biodynamic farms have extensive practices designed to build soil, improve robustness of crops and ensure bio and nutrient diversity. Instead of monocultures, these farms grow huge arrays of different vegetables and fruits. If a biodynamic farm raises animals they are given their natural, preferred diet of grass (for cows) or bugs and seeds (for birds). The animals are treated well and fed well, and are healthier as a result. If you want to learn more about the differences between conventional agriculture, big organic agriculture and biodynamic farming I highly recommend Michael Pollan’s excellent book, The Omnivore’s Dilemma, and Joel Salatin’s latest book, Folks, This Ain’t Normal.

Interestingly, despite the wide range in the quality of foods that qualify as organic, the Stanford study did find some significant differences. Organic produce contained significantly more phenols, the cancer fighting chemicals found in red wine, green tea, chocolate and many fruits and vegetables. However, this finding was glossed over in favor of the non-significant differences found between vitamin C, betacarotene and vitamin E levels in organic versus conventional foods.

It is reasonable to hypothesize that organic agriculture (at least in some cases) would be more nutritious because the soil standards for organics are much higher than for the depleted, synthetically fertilized conventional fields. Soil quality and weather (the raw ingredients) are by far the biggest factors in the nutrient levels of produce, with freshness and storage methods being next in line. Indeed, organic agriculture typically has more minerals and the Stanford team confirmed they contain significantly more phosphorus. But there is so much variety among plants, and from season to season, that you shouldn’t necessarily expect large, consistent differences in the levels of common vitamins like C and E from genetically identical plants.

That the Stanford team found measurable differences in total phenol content is pretty impressive. There are dozens of phenolic compounds that could benefit health in different and subtle ways. Nutrition science still can’t explain the benefits of all these nutrients, but having more of them certainly seems like a good thing.

Still lack of pesticides, not better nutrition, is the most commonly cited reason for buying organic over conventional foods. Pesticides are designed to kill things, and have been shown repeatedly to be dangerous for farm workers and other wildlife. They also accumulate more in the bodies of people who eat conventional produce compared to those who eat organic, and susceptible populations such as children, pregnant and nursing women, and the elderly are at particular risk. The Stanford study confirms organic agriculture has substantially fewer pesticide contaminations, but for some reason this finding was also glossed over since the conventional produce levels “didn’t exceed maximum allowed limits.” Logically, however, if limiting pesticide exposure is important to you (as it should be) organic produce is the better option.

The animal studies were even more encouraging. Small but significant improvements in fatty acid profiles were found for organic milk and chickens, which contained more healthy omega-3 fatty acids. More importantly, antibiotic resistant bacteria, the kind that are becoming more common (and deadly) in our own hospitals, were 33% more likely to be found on conventional meat products than on organic meat. Antibiotic resistant bacteria being created on industrial farms is one of the scariest threats to human health in modern history, and any measures that limit their proliferation should be seriously considered.

From this study it seems reasonable to conclude that organics, even industrial organics, are superior to conventional foods in some ways. Organic farms cannot use synthetic fertilizers or pesticides, sewage sludge (yes, human sewage is used on conventional food), irradiation or genetically modified organisms (GMOs), and must help maintain or improve soil quality. These practices are much better for the environment, significantly limit the amount of pesticides you are exposed to, reduce the proliferation of dangerous pathogens and may be more nutritious.

Organic agriculture certainly sounds like it has some advantages over conventional ag to me.

Do you buy organic? Why?

Photo by Mr. T in DC

“I’ve always wondered what the scientific perspective of alcohol consumption is. I have been doing some research but the actual effects of it on the body range from beneficial to cancerous.”

The clinical science on alcohol consumption is vast and diverse. It’s easy to find studies that demonstrate the benefits of alcohol, but it is equally common to find research showing its dangers. Sorting through the data is not trivial, and getting the right answer from news reports is virtually impossible.

Let’s start with the facts:

1. Alcohol is addictive

Alcohol addiction is one of the most well-understood and dangerous risks of drinking. A propensity for addiction can run in families, but can affect anyone who drinks in excess. None of the health benefits of alcohol can negate the destruction caused by addiction, and anyone who drinks should be careful to avoid this terrible condition.

2. Alcohol damages the liver

Alcohol metabolism occurs in the liver and can cause severe damage when consumed in large quantities. Liver damage can usually be reversed if alcohol consumption stops.

3. Alcohol is associated with breast cancer (sort of)

Drinking is weakly associated with an increased risk of breast cancer. This is likely because alcohol increases aromatase activity in the human body, which increases estrogen production. Estrogen imbalance is a known cause of breast cancer. However, the association between drinking and breast cancer is negated by sufficient folate intake. Folate or folic acid is a B vitamin found in leafy green vegetables, fruits and legumes (and fortified foods). In other words, a healthy diet protects against alcohol induced breast cancer risk.

4. Alcohol protects against mortality from heart disease

Drinking alcohol reduces your risk of dying from a heart attack by preventing blood clotting. This effect is not limited to red wine, all spirits elicit substantial protection. The association appears to be dose-dependent, meaning that the more you drink the more protection you get. HOWEVER, you start raising your risk for the above mentioned problems with every additional drink per day. For men the ideal dosage is 2 drinks per day, for women it is 1 drink per day.

5. Alcohol raises good HDL cholesterol

Moderate drinking also reduces your risk of getting heart disease in the first place by raising beneficial HDL cholesterol without raising LDL cholesterol. Low HDL is a serious problem in America, and alcohol could be a significant benefit for some people. Here are other ways to raise your HDL cholesterol.

6. Red wine may slow aging

Aging research has been revolutionized by the discovery of a compound in red wine called resveratrol. Resveratrol has been shown to slow aging substantially in several model organisms. Though the effect in humans is still unknown, red wine is associated with many benefits that seem to go above and beyond the benefits of alcohol in general.

7. Red wine may protect against Alzheimer’s disease

Several studies have shown that red wine is associated with a decreased risk for Alzheimer’s Dementia, a devastating neurodegenerative disease that affects 1 in 4 people over the age of 90. The mechanism of action is unclear, but the benefits may be linked to the effect of red wine on fatty acids in the blood (raising the good stuff), or by slowing the aging process itself.

8. Alcohol causes accidents and behavioral problems

Even relatively safe levels of drinking can be deadly when combined with poor decision making. If you do choose to drink alcohol, always be sure that you’re in a safe environment and can get help if you need it. Being safe sometimes, or even usually, is simply not good enough.

There are plenty of good reasons to avoid alcohol if you choose, and many of the benefits can be garnered by simply increasing the amount or intensity of your daily physical activity.

However, the evidence is pretty clear that moderate alcohol consumption (1-2 drinks per day) can improve health and may be an important component of a healthy lifestyle. This is even true for those who pick up the habit later in life.

And last but certainly not least, some of the best times of my life have been over a drink with friends. And I guarantee you most of us aren’t thinking about our heart health while enjoying a great bottle of wine. As long as you consider safety first, never forget that smiling is one of the healthiest things you will ever do.

Here’s a fun question: what’s your favorite drink??

Originally published July 28, 2010.

Photo by Irwin-Scott

I’ve had about a zillion people ask me about a new study that came out in the Archives of Internal Medicine this week linking red meat consumption to increased mortality.

Naturally some people are afraid their carne asada habit may be dooming them to an early death, and who could blame them with headlines like these?

On the other hand, I suspect many of you have dismissed the study out of hand because it conflicts with your world view that animal foods only make good things happen.

But in the interest of science and being grown ups, let’s take a look at the study and see what we can learn.

First, it is worth mentioning that the study was fairly well-designed and conducted by a respectable team of scientists at Harvard. They reanalyzed data from two large prospective cohort studies: The Health Professionals Follow-Up Study (HPFS, 1986-2008) and the Nurses Health Study (NHS, 1980-2008).

Both cohorts were large groups of health care professionals, which would presumably limit differences in education and income that can often confound health studies. The participants filled out regular food frequency questionnaires that have been previously validated as decently reliable (though food frequency questionnaires are notoriously unreliable).

Importantly, all the participants were eating Western diets during what have come to be known as the least healthy decades in US history. Also important, during the course of the study both red and processed meat consumption declined in both men and women.

“The mean daily intake of unprocessed red meat dropped from 0.75 to 0.63 servings from 1986 to 2006 in men and from 1.10 to 0.55 servings from 1980 to 2006 in women.”

The authors never comment on what this reduced consumption means for their analysis, however, since they “created cumulative averages of food intake from baseline to death from the repeated food frequency questionnaires.”

According to the report, people who ate the most red meat were more likely to smoke, drink, eat far more calories and be overweight. They were also less likely to exercise and eat healthy foods like fruits, vegetables, whole grains and fish. Basically they were less healthy people with less healthy habits.

The authors claim to have controlled for such lifestyle factors by doing statistical corrections for these variables, which is the industry standard for this type of analysis. They also performed a sensitivity analysis to see if any other dietary variable (including glycemic load) may have impacted their results. They did not detect any significant differences when controlling for these factors, which I admittedly find surprising.

To their credit, the authors made an effort to distinguish between processed and unprocessed meats. Given the time during which the study took place, however, it’s unlikely that any of the participants were eating non-industrial, grass-fed and pastured meat. I think this is an important point, particularly when considering cancer mortality, since toxic compounds tend to accumulate in the fat of animals.

In their analysis the authors estimated that for every one serving of red meat per day (defined as 3 oz), total mortality risk increased by 12% (20% for processed red meat alone, 13% for unprocessed). Heart disease risk increased by 16% for total red meat (21% for processed red meat, 18% for processed), and cancer risk increased 10% for total red meat (16% for processed, 10% unprocessed).

To help put this in perspective, in the Nurses Health Study (the larger of the two) the group that ate the least meat consumed about a 1.5 oz (half a deck of cards) of meat per day and the group that ate the most consumed around 6.5 oz of meat per day (here’s the data I’m pulling from, using the 3 oz serving size for conversion).

Remember, these numbers are for daily consumption. For the highest group, that’s nearly 3 pounds per week (45.5 oz). For the lowest group, under 1 pound (10.5 oz). Realistically, the lowest group probably ate red meat 1-2 times per week, while the highest group ate it once or twice a day. How we got from here to “all red meat will kill you” isn’t exactly clear.

Interestingly, when they did an analysis to see the specific effect of saturated fat in meat it accounted for only 4% of the 16% estimated risk. This is fairly low considering that saturated fat is supposedly what makes meat so bad for us by raising cholesterol. But since the authors say that saturated fat could account for some of the increased risk, can we at least assume that those eating the most meat were more likely to have higher cholesterol? Not so fast. It turns out that in both cohorts, those in the lowest group of meat consumption were the most likely to have high cholesterol. (Thanks Denise Minger for making this astute observation).

So what about the meat is killing us exactly? In addition to saturated fat, the authors also estimated that heme iron in meat (assumed to be a risk factor for some diseases) can account for another 5% of the risk, but they do not elaborate on how this might work. It is unclear what else about red meat may be increasing mortality risk, though preservation methods are suspected for the higher risk associated with processed meats.

The authors also used some fancy statistical magic to estimate what would happen if the participants theoretically replaced one “daily” meat serving with an equal portion of either fish, poultry, nuts, legumes, low-fat dairy or whole grains and determined that mortality risk would decline 7%, 14%, 19%, 10%, 10% and 14%, respectively. It is important to remember though that *ahem* these are not real experiments but merely estimations based on the numbers and statistical models used in this study. At best an analysis like this can generate a hypothesis that could then be tested in a controlled trial.

Fortunately controlled studies replacing meats (oh, and all the other crap in the Western diet) with other nutritious, whole foods have already been done. For example, in the Lyon Diet Heart Study (1988) a group of patients who had already had a heart attack were instructed to change their diets. One group went on the low-fat American Heart Association diet, the other group adopted a Mediterranean style diet that included lots of green and root vegetables, fruits, legumes, more fish and poultry, less red meat, olive oil and no cream. After only 3 years the study was stopped by the ethics and safety committee because the Mediterranean diet group had a 70% reduced risk of death compared to those on the low-fat diet.

Studies have consistently shown that replacing some dietary meat with fish and other sources of omega-3 fatty acids reduces the risk of heart disease. However, replacing red meat with anything else (even olive oil) seems to be pointless. For this reason I’ve always been skeptical that red meat is uniquely bad when the simpler explanation would be that eating more fish is uniquely good. I don’t see how this new analysis of old studies changes anything.

Lastly, although the authors included controls for lifestyle factors I’m highly suspicious that people with so many unhealthy habits are at an increased risk of death primarily because of meat consumption. Consequently, all that I’d feel comfortable concluding from the new analysis is that in the context of a Western diet, eating something other than meat every once in awhile is probably a good idea. Outside of the Western diet? It’s much harder to say.

What are your thoughts on the study?

Photo by Robyn’s Nest

Artificial sweeteners and sugar substitutes can be very appealing to people looking to cut their calories or control blood sugar, and I get a lot of questions about them. Generally I don’t recommend processed or sweetened foods and encourage people to break free from regular sugar consumption, but I recently discovered coconut palm sugar and decided to look into it.

Coconut palm sugar has garnered attention as being a low-carb sugar substitute that is more nutritious than typical granulated sugar. Because of its complex flavor it is also gaining a reputation in foodie communities, with establishments like the popular Samovar Tea Lounge in San Francisco switching 100% of its sweeteners over to coconut palm sugar.

Pure coconut palm sugar is a natural product made from the nectar of the coconut palm tree. There are several different varieties of palm (Palmyra, date, etc.), and “coconut palm” specifically refers to the coco nucifera plant.

Most of the “palm sugar” commonly sold in Asian markets is not pure coconut palm sugar but is blended with other fillers such as white cane sugar. Pure certified organic coconut palm sugar is sold under the brand name Sweet Tree in the US, and can be found at some natural food stores.

The information in this article applies only to 100% pure coconut palm sugar. Check your labels carefully.

Pure coconut palm sugar reportedly has a naturally low glycemic index (GI)–a measure of how food impacts blood sugar–which has led some people to claim that it is a valuable sugar substitute for people with diabetes or those looking to control blood sugar (the low-carb camp). Indeed, a lower GI may be a good indication that a food is safer for diabetics, though it is not a guarantee.

When I first saw that coconut palm sugar has a low GI I figured it would be composed largely of fructose, similar to the popular sweetener agave nectar (and high-fructose corn syrup). Fructose does not impact blood sugar because it is transported directly to the liver and converted to fat. For an explanation of this mechanism, check out Dr. Lustig’s video on the dangers of fructose.

I was surprised to find, however, that coconut palm sugar is reportedly very low in fructose, and its main sugar component is sucrose (aka table sugar). What confuses me is that the GI of coconut palm sugar is supposed to be 35, while the GI of sucrose is 64. Something doesn’t add up.

I could only find a summary of how GI was measured and not the published study itself. Also, this information was only available on the website of a company that sells coconut palm sugar. This doesn’t mean the number is inaccurate, but it is a little suspicious and I’d like to see the study repeated by another credible source or two before taking it as fact.

(UPDATE: At one time I found reports of newer tests that found discrepancies with the reported GI of Sweet Tree products, but the page has since been taken down)

The number of calories in coconut palm sugar is almost identical to the number in regular table sugar and its closer relative, brown sugar. But coconut palm sugar is notably higher in various micronutrients, probably because it is less processed than industrial sugars.

But does anyone really eat sugar for health benefits?

There are a number of good reasons to consider using coconut palm sugar as a substitute for white or brown sugar in your kitchen. For me the most obvious benefit is that it tastes amazing, similar to brown sugar but with a rich complexity I’ve never tasted in industrial sugars.

Overall coconut palm sugar is a tastier and possibly healthier substitute for granulated or brown sugar. I wouldn’t go so far as to call it a health food, or even low-carb just yet.

Substitute coconut palm sugar for traditional sugar at a 1:1 ratio in normal cooking and baking.

Have you tried coconut palm sugar? What do you think?

Originally published March 10, 2010.

Photo by Lord Jim

“What do you think of the Paleo diet which advocates zero grain consumption?”

The Paleolithic diet is one of the most rapidly growing diet trends of the past several years. Followers of the Paleo diet argue that humans have not evolved to eat agriculture-based foods and can only achieve optimal health by consuming a hunter-gatherer style diet. Thus the Paleo diet is completely devoid of grains and legumes, and also shuns dairy, salt, refined sugar and processed oils. The diet is composed primarily of meats, fish, vegetables, fruits, roots, nuts and seeds.

(The Wikipedia article on the Paleo diet is actually pretty good if you’d like to read up on the details. I particularly like the Opposing views section.)

Like most diets the Paleo diet has a little bit of good science behind it, but also a lot of logical leaps and baseless assumptions. The evolutionary argument that humans are somehow maladapted to agriculture-based diets is particularly unconvincing (resting on many unproven assumptions), yet is the fundamental premise on which the Paleo diet bases its recommendations.

The reasoning behind the Paleo diet is less interesting to me, however, than the impact of the diet itself. Will “eating like a caveman” really help you be healthier?

Possibly, but not necessarily.

The most obvious advantage of the Paleo diet is the lack of processed foods. There is ample evidence that societies on traditional diets boast far better health than those on modern, Western diets–and the hallmark of modern diets is food processing. Paleo diets therefore are low in sugar, refined carbohydrates, trans fats, excess salt and pretty much everything else that leads to “diseases of civilization.”

Paleo diets are also abundant in healthy, nutrient-rich foods such as vegetables, fruits, nuts, fish and meats. I have no doubt that anyone willing to stick to a Paleo eating plan will have a healthy weight and remain virtually free of heart disease, diabetes, hypertension and may even have lower rates of cancer.

But the question still remains, is it necessary to eat Paleo to be healthy?

This is where I take issue with the Paleo philosophy. While a diet completely free of processed foods is undeniably healthy, the Paleo diet goes beyond this and demands considerable sacrifice.

Paleo diets do not allow for any grains or legumes. This pretty much eliminates every traditional cuisine on earth including Japanese, Italian, Indian and Greek. Not only is this a culinary tragedy, it ignores the fact that these cuisines feed some of the world’s healthiest and longest-lived individuals.

Traditional, global diets that exclude highly processed foods but also include grains and legumes have been some of the most successful for health. Diseases of civilization are only problematic in Western cultures where processed foods make up a large proportion of the calories and few whole food are consumed.

Proponents of the Paleo diet argue that it is necessary to eliminate grains and legumes because they contain “antinutrients,” substances that can interfere with the body’s absorption of other important vitamins, minerals and proteins. However, well-nourished individuals who eat a varied diet of unprocessed foods (including grains and legumes) are not nutrient deficient and are generally healthy.

Given that it is possible to thrive on a diet that includes some grains, legumes and even small amounts of processed foods, one must question if giving up the culinary joys of travel and global cuisine are really worth the sacrifice.

In my experience, food substitutions and modified recipes designed to mimic traditional meals can sometimes be tasty but can never replace true authenticity.

Another contention I have with the Paleo diet is the assumption that the same eating patterns will work for everyone. People’s lives differ in countless ways. We each have different levels of daily activity, demands on our time and food preferences. We also have different genetic backgrounds, which can result in significant differences in metabolism and hormone levels. These individual variations make dietary needs different for each of us.

Because of our individual differences, there is undoubtedly a percentage of the population that thrives on the Paleo diet and finds it easy to stick to and achieve results. Hooray! However there may also be a segment of the population (myself included) that finds living without grains and legumes to be chronically unsatisfying and unsustainable.

Try telling a foodie they can never eat cheese or drink wine again and see how far you get pitching a Paleo diet.

If you currently eat a typical Western diet with little variety and many processed foods, tend to have better success following rigid diet plans, and have no qualms about giving up or modifying traditional meals to meet your dietary demands, then you might have luck following the Paleo diet. However there is no reason to believe it is the only path to good health.

The best diet is the one that works for you. Finding a healthstyle you can embrace and enjoy is essential if you want to build a lifetime of healthy habits.

Do you follow a Paleo diet? What do you think?

Originally published February 22, 2010.

Photo by Werwin15

The science of aging is among the most dynamic and provocative in modern biology. Over the past two decades we have seen a virtual explosion in research investigating the molecular and behavioral systems that control the aging process. But the more researchers uncover about the science of aging, the more questions emerge.

Dietary restriction has long been considered the most potent regulator of aging. Restricting food intake by any means induces a series of metabolic changes in organisms from yeast to primates that serve to extend life. Studies are currently underway to investigate the ability of dietary restriction to extend life in humans.

Several biological changes are known to occur upon the onset of dietary restriction including a decline in reproductive ability, increased stress resistance and a slowdown of some metabolic processes.

Insulin signaling was among the first molecular pathways to be identified in the regulation of aging, and offered a direct tie between diet and the aging process.  In 1998 UCSF scientist Cynthia Kenyon showed that removing an insulin receptor gene (daf-2) in worms could double their lifespan. Her lab later showed that removing another insulin signaling gene (daf-16) could extend life even longer. I spoke to Kenyon about the relationship between diet and aging for this article.

Blocking insulin signaling in these worms did not just prevent the worms from dying and allow them to age longer. Instead the aging process actually slows so that older worms continue to behave like young worms. Also, as these experiments were repeated in different animals, it was shown that lowering insulin signaling also helps protect animals from stress and diseases such as cancer and heart disease.

Insulin is released as a direct response to glucose in the blood. This means that any time you eat a meal with carbohydrates, you are increasing your insulin signaling and likely accelerating aging. But this does not mean that you will live forever if you stop eating carbohydrates.

Interestingly, protein metabolism also contributes to accelerated aging, but through a different mechanism. Even more intriguing is that restricting protein increases lifespan to a greater extent than restricting sugar.

So is it simply calories that promote aging?

Probably not. For one thing, the effect of a calorie from protein is greater than a calorie from carbohydrate, making it unlikely that a calorie is the basic unit of impact. Second, there is evidence that calories are not required to accelerate aging.

Recent studies have shown that the mere act of smelling food can reduce lifespan. The mechanism for this effect is still unknown, but seems to be tied to respiration.

According to Kenyon it is clear that “sensory perception influences lifespan,” at least in worms and flies.

Thus it is likely that aging is controlled by the interaction of several pathways, including metabolism, respiration and stress. Importantly, however, lifespan seems to be dependent on a handful of specific pathways rather than global changes in cellular function or breakdown. The idea that aging is an inevitable function of time must be put aside given the evidence that it is controlled at a genetic and environmental level.

This makes sense when you think about it. Different organisms exhibit vastly different lifespans and rates of aging that are too great to be explained by some kind of universal cellular breakdown. A more parsimonious hypothesis is that organisms differ in specific genetic factors that, combined with environmental influences, regulate lifespan.

So how should we mortal humans react to these findings?

The genes linking diet and aging are highly conserved through evolution, indicating that there is a great chance human aging is sensitive to diet. Indeed, insulin-related genes have been found to be important in long-lived human populations. This suggests that the pathways discovered in worms and other organisms have similar functions in humans.

What is not clear is how much influence diet has on lifespan and to what extent we are able to manipulate it. It is already known that abnormal insulin activity in humans is linked to higher disease rates, especially “diseases of civilization” such as heart disease, hypertension, type 2 diabetes and cancer. And these diseases are clearly associated with diets rich in processed foods, especially refined carbohydrates.

The effect of protein consumption on lifespan in humans has yet to be investigated. Envisioning an experiment that would test the influence of smelling food on human aging is difficult to even imagine.

Although direct evidence is not available, there is good reason to suspect that a diet with low glycemic load may extend human lifespan. In November 2009, Kenyon’s lab reported that adding glucose to a worm’s normal diet shortens lifespan, but has no effect on the long-lived worms that lack insulin signaling genes daf-2 and daf-16. This discovery prompted Kenyon herself to adopt a low-carbohydrate diet.

Despite this there is still not sufficient evidence to recommend a calorie restricted diet for humans to extend life, largely because optimal nutrition levels for a given individual are unknown. However, most people would benefit vastly by eliminating processed foods and refined carbohydrates from their diets as much as possible.

Focusing on fresh, whole foods, enjoying an occasional glass of wine, avoiding smoking and getting regular exercise can add 14 years to the life of an average person. Maintain a healthy weight as well and your outlook gets even better.

Would you change your diet to be healthier and live longer?

Originally published February 3, 2010.

Photo by Venex_jpb

If there is a single subject that befuddles the health-conscious eater, it is undoubtedly carbohydrates.

Most of us have seen the impressive results of at least temporarily restricting carbs, but studies examining the long-term effects of carbohydrate restriction are often ambiguous. Also, while some experts argue fervently for a low-carb lifestyle, some nutritionists still warn about the dangers of eating too much fat or protein.

So how do we know what to believe?

A full examination of the science behind carbohydrate metabolism is beyond the scope of a single blog post, and is in fact not entirely understood by the scientific community (for a thorough review of this topic read Gary Taubes’ book Good Calories, Bad Calories, which I have reviewed here).

However, there are a few things we do know about carbohydrates that are worth pointing out.

Lesson 1: Refined grains contribute to nearly every chronic disease in modern civilization.

It is universally agreed in the nutrition community that refined, processed carbohydrates are the worst things to eat on the entire planet.

And it is impossible to overstate how remarkable this is.

The nutrition community is one of the most disagreeable bunches in all of science. But across the board–from vegans like Colin Campbell to carnivores like Robert Atkins–not a single one of them considers processed carbs to be nutritionally neutral. They all consider them dangerous.

Without question, refined carbohydrates contribute to poor health.

Lesson 2: Vegetables protect against nearly every chronic disease in modern civilization.

Where things start to get more complicated is with unrefined carbohydrates, and the various iterations of this definition. There is ample evidence that the carbohydrates contained in vegetables are not harmful, and possibly beneficial.

To call these vegetable carbohydrates “fiber” is to oversimplify the science, but suffice to say that vegetables are good for you and contribute to your good health.

This is also generally agreed upon.

Lesson 3: Whole grains are different from intact grains.

Few people will argue against my first two points. But bring up whole grains and you will unleash a fury of controversy. Some people believe whole grains to be the cornerstone of any healthy diet, while others consider them superfluous and possibly detrimental to good health. You can find dozens of PhDs and MDs to back up your claims no matter what camp you align with.

So why is there so much disagreement? What does the science say?

The problem is that nutrition science conducted in free-living humans is virtually impossible to interpret. This is largely because the studies are so difficult to control and people’s behavior and self-reporting are so unreliable. Another problem is that the definition of “whole grains” has been watered down to a point where it is virtually meaningless.

One reason whole grains are hard to identify is because the US Food and Drug Administration (FDA) has created a definition that is friendly to food companies, but not to consumers.

The FDA requirements for a manufacturer to use the term “whole grain” on its label (along with the respective health claims) are as follows:

“Cereal grains that consist of the intact, ground, cracked or flaked caryopsis, whose principal anatomical components – the starchy endosperm, germ and bran – are present in the same relative proportions as they exist in the intact caryopsis – should be considered a whole grain food.” (emphasis added by me)

Get it? To be considered “whole,” grains do not actually have to be intact.

Thus food manufacturers create products using this loose definition to their advantage, demolishing grains as normal, then adding back the required ratios of grain parts (germ and bran) to meet the standard.

This is how products like Froot Loops get spiffy health labels claiming they lower heart disease when any unbiased nutrition scientist would agree that, with 41% sugar by weight, Froot Loops almost certainly contribute to heart disease.

On the other hand, there is compelling data that intact whole grains contribute to better health.

Lesson 4: Eating grains is a personal choice, not a nutritional imperative.

The good news is that it is really easy to tell the difference between fake “whole” grains and intact whole grains. If a food actually looks like a grain (i.e., it retains its original form and bran covering), then it is an intact grain. If it looks like a Cheerio, chip, loaf of bread or pasta with a “whole grain” label, then it is a fake whole grain.

People following a primal or paleo diet will argue that this difference is irrelevant and that all grains (and legumes?!) are unnecessary for good health. Personally I disagree, but remain fairly neutral on the personal choice of removing grains from the diet entirely.

Grains do not appear to be necessary for survival (Inuit tribes survive without them), but optimal nutrition may require slightly more effort than would be necessary following a traditional balanced diet.

This is generally how I feel about all healthy, restrictive regimens such as vegetarian, vegan and raw diets. You can make it work for yourself if you are willing to make sacrifices and put in the effort.

However you should be aware that for many people, myself included, cutting whole grains out of your diet completely is extremely difficult and, if you ask me, unnecessarily painful.

Conclusion

When making food choices about grains, the critical question is not whether or not a food is “whole” grain but whether the grain is intact. For this reason, it matters very little if you substitute “whole grain” products for regular refined products such as pasta.

Examples of intact grains are oats, barley, brown rice, whole wheat, quinoa (sort of) and faro. White rice is not a whole grain, and is closer to a refined grain than a whole grain.

For optimal health, processed and refined grains should be eaten very sparingly. Small amounts such as those eaten in traditional cultures can be part of any healthstyle, but including them is a personal choice that will depend on your own goals and preferences.

The irony is that if you are able to remove processed foods from your diet, the way you eat could probably be described as low-carb. But this label really undermines a healthstyle based on real food.

Though I eat relatively few grains compared to most Americans, I cringe when I see the shining example of low-carb living, The Atkins Diet website, with images of fake pancakes and pasta plastered all over it. If that is what low-carb is, I want nothing to do with it.

Processed food is still processed food, whether the carbohydrates have been synthetically removed or not. Stick to eating real food and you’ll never have to worry about carbs.

Do you count your carbohydrates?

Originally published November 25, 2009.

Garlic

People often say that garlic has medicinal properties. Some claim it lowers blood pressure, others swear it helps cholesterol and reduces clotting, and some even think it protects against cancer. I’ve also heard that garlic is “healthier” 10-15 minutes after it has been crushed or minced. Is any of this true?

The Science of Single Foods

As someone who regularly reads the scientific literature on the health benefits of food I can assure you that this is not an easy question to answer. The problem is that the effect of any single food on human health is likely to be small at best, and small effects are very difficult to detect with reliability. Studies must be incredibly well-designed to contribute anything of value to our understanding of how a food works in the human body. Also, many studies must be taken together in context for the data to be evaluated properly.

I have been researching this garlic question on and off for months and feel only slightly more confident today than I did when I started. To summarize, there are a good number of studies addressing the health value of garlic, but very very few of them are well-designed and published in reputable journals. The problem with having a large number of poor-quality studies is that results are often conflicting and difficult to interpret. Thus, when another scientist comes in to do a meta-analysis (pooling data from many studies and re-analyzing it for stronger statistics) the findings are usually inconclusive.

However, inconclusive findings do not enable me (or anyone) to say there is no benefit. What I can say is that more research is needed and if there is a benefit it is likely to be small. (How unsatisfying is that?!). But personally I would still recommend eating garlic for health. Why?

Small Benefits Are Important

Although we cannot say exactly why garlic is good for you, it is almost certainly not bad for you. Moreover, although it is difficult to attribute a particular health benefit to a single food, we do know that people who eat the most vegetables tend to be healthier than people who fewer.

Many nutrition scientists are beginning to suspect that the benefit of foods like garlic are primarily relevant in the context of a whole diet and cannot be evaluated independently. This means that it is less important that the individual studies I mentioned earlier are inconclusive, because they are likely not sensitive enough to evaluate the complex interactions of whole foods and food combinations on human physiology.

The Best Reason To Eat Garlic

The most important thing you can do for your health is eat a diverse diet of natural, unprocessed foods. Garlic is an amazing ingredient that imparts a unique and wonderful taste to the food it is cooked with. If you like garlic and it encourages you to eat your vegetables, then it’s good for you.

If it makes you feel slightly better knowing that it may help your heart or reduce inflammation, that’s awesome but less important.

What About The Crush?

If you do hope garlic can add to your health, is there any benefit in crushing it early? Probably.

Scientists have long suspected that the active ingredient in garlic is a substance called allicin. A recent study from Queen’s University showed that it is actually a decomposition product of allicin that has the most potent antioxidant activity.

Interestingly, allicin is created from an enzyme called alliinase that is not released from plant cells until they are damaged. Alliinase is what gives garlic (and onions) their strong odor and is thought to be a self-defense mechanism for these plants. When garlic is crushed, alliinase becomes active and begins creating allicin. As allicin is created and breaks down, the antioxidant potential of garlic is dramatically increased. Optimal antioxidant levels are created about 10 minutes after garlic is crushed.

It has not yet been shown that this increased antioxidant activity is a benefit to humans, but the principle is compelling enough to try to remember to crush your garlic a little early. If you are anything like me though, this feat is almost impossible. Apparently garlic hasn’t done that much for my memory.

What are your favorite reasons to eat garlic?

Originally published March 27, 2009.