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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.

Tags: bread, carbs, intact grains, paleo diet, pasta, processed foods, quinoa, raw food, real food, refined carbs, rice, vegan, vegetables, vegetarian, whole grains

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.

Tags: allicin, alliinase, crushed garlic, garlic, minced garlic

Enough people have asked me if the kind of cholesterol in egg yolks is good or bad (hint: it’s neither) that I think it is time for a brief tutorial on this misunderstood molecule.

Rather than put you to sleep with a watered down version of a Wikipedia article I decided to explain the interaction of diet and cholesterol in a short video. Hopefully this will help clear up what cholesterol is and how you should eat to minimize your risk of heart disease.

As always, feel free to drop me questions in the comments.

If you like this story follow me on the new Digg!

Further reading:

• How To Raise Your HDL Cholesterol
• Intact Grains vs Whole Grains
• How To Make Eggs Taste As Good As Bacon
• Book Review: Good Calories, Bad Calories

Tags: cholesterol, eggs, HDL, heart disease, LDL

Photo by markhillary

Last month The American Journal of Clinical Nutrition published a meta-analysis of 21 studies concluding that saturated fat is not linked to heart disease–a finding that flies in the face of 20th century nutrition dogma.

Despite the tremendous impact such information would have on the field of nutrition however, the research was largely ignored by mainstream media outlets.

The meta-analysis performed by scientists at the Children’s Hospital Oakland Research Institute was funded by the National Dairy Council and the Unilever corporation, two institutions with a vested interest in selling food products to consumers. The study was also funded by the National Institute of Health.

Technically funding source should not impact scientific outcomes, but analyses have repeatedly shown that industry sponsorship can strongly predict research conclusions that favor the source of funding.

I asked Marion Nestle, professor in the Department of Nutrition, Food Studies and Public Health at NYU, about the specific impact of industry funding on a meta-analysis of this nature.

“Meta-analyses are particularly subject to investigator bias (conscious or unconscious) because of the selection criteria for inclusion.”

So while this study may provide another clue about the relationship between saturated fat and heart disease, caution should be taken when interpreting the results.

Conflict of interest is a serious concern in science that is used to guide health policy and consumer behavior. In this case the influence of industry sponsorship would be especially unfortunate since an impartial evaluation of the link between saturated fat and heart disease is greatly needed.

Saturated fat is most commonly associated with animal products like beef and pork, and is known to raise cholesterol. Since high cholesterol is considered a biomarker of heart disease, it has long been assumed that saturated fat contributes directly to America’s number one killer.

But while this argument seems to make intuitive sense, a direct causal relationship between saturated fat and heart disease has never been established. Moreover, evidence is accumulating that cholesterol in general is not the best predictor of heart disease and that refined carbohydrates are a bigger problem.

Thus there is a real need for rigorous science regarding the role of saturated fat in heart health and other diseases.

“My take on this one is that it is one more piece of evidence that saturated fat may not be AS important a determinant of heart disease risk as is sometimes believed-at least in the kinds of studies included in the analysis.  These, of course, do not paint a complete picture of the situation.”

Saturated fat is unlikely to make or break any diet in terms of overall health, let alone heart disease in particular. General dietary patterns consistently prove to be better predictors of long-term health than any single food or nutrient, and anything we discover about saturated fat is unlikely to change this.

“In any case, this is another example of what happens when you look at single nutrients outside of their dietary context.”

While we’re waiting for science and industry to battle it out in the lab, focus on eating real, unprocessed foods most of the time and don’t get too hung up on the details.

What do you think of industry sponsorship in nutrition studies?

Update: After speaking with readers and colleagues I have made some revisions to this article to clear up my stand on this research. I do not intend to imply that the investigators of this study were influenced by their funding source, only that caution should be used when interpreting the results of any meta-analysis where there is a potential conflict of interest.

Tags: American Journal of Clinical Nutrition, dietary pattern, food industry, heart disease, Marion Nestle, saturated fat

Organic Vegetables

There has been a lot of back and forth trash talking between fans of organic and fans of conventional produce ever since a new review study by the Food Standards Agency (FSA) reported no nutritional superiority for organics. Let’s take a look at some of the opposing arguments and have a vote.

Since the publication of the review last week I have been collecting the opinions of various experts around the internet.

A few fabulous articles are worth noting:

• Organic Versus Conventional Food: UK Report Flawed by Paula Crossfield at Civil Eats. This is the best analysis I have found. If you only have time to read one article of criticism, make it this one.
• Organic Center Response to the FSA Study is particularly interesting because it points out that the FSA actually did find a nutritional benefit of organic foods, but simply decided the differences were not important.
• Soil Association response to the Food Standards Agency’s Organic Review presents some additional scientifically valid criticisms/omissions of the report.
• Today’s huge flap about organics. NYU professor of nutrition, Marion Nestle, offers her usual dose of common sense: doesn’t taste matter to anyone?

Key criticisms of the FSA report:

1. The nutrient analysis is questionable and incomplete.
2. Findings contradict conclusions of other scientists.
3. Report does not account for the presence of toxins and contaminants.
4. Conflicts of interest may exist among the investigators of the report and agribusiness.

So what do you think?

Do you believe the review? Think it’s a flawed piece of industry propaganda? Still undecided? How will this study affect your buying habits?

Do you even think about these things before making food purchases?

Vote in the poll and leave additional thoughts in the comments.

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Tags: organic