For the Love of Food

by | Jun 28, 2013
For The Love of Food

For The Love of Food

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

This week learn how refined carbs trigger cravings, how to make body fat burn extra calories and how not to talk to your kids about weight loss.

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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For The Love Of Food

by | May 4, 2012

For The Love of Food

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

This week we explore how vegetables make you prettier, a consensus on what’s killing us and why you don’t walk enough.

Want to see all my favorite links? Be sure to follow me on on Delicious. I also share links on Twitter @summertomatoGoogle+ and the Summer Tomato Facebook page. I’m very active on all these sites and would love to connect with you.

Links of the week

What inspired you this week?

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Can You Live Longer By Cutting Calories?

by | Mar 30, 2011

Photo by Werwin15

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.

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Book Review: Good Calories, Bad Calories

by | Jan 6, 2010

good calories bad calories cover

Good nutrition advice is not easy to come by, but we have to start somewhere.

It is probably obvious to most of you that public education on diet and health is vastly inadequate. We learn virtually nothing in school, and what they do manage to pass on is less-than-useful or just simply wrong.

Advice changes from year to year, sometimes drastically.

Everyone claims to be a nutrition expert, but very few people are actually trained enough to understand the complex and sometimes contradictory findings made by scientists in the field.

But although there are few sources you can trust, some books do stand out as valuable for understanding the basics of health and nutrition. Good Calories, Bad Calories by Gary Taubes is by far the most thorough I’ve found, and is essential reading for anyone who has an honest desire or need to understand how diet impacts health.

Taubes makes a detailed and compelling case that refined carbohydrates are the primary cause of weight gain and “diseases of civilization” such as heart disease, hypertension and diabetes. In my view, any honest and opened-minded scientist would have to largely agree with him.

GradeAGood Calories, Bad Calories is 468 pages and contains over 100 additional pages of references, which is nothing short of astonishing. Taubes explores every aspect of the science behind weight control including the most puzzling and frequently ignored evidence, which he argues is the most important.

Scientists depend on statistics, but have a tendency to ignore outliers which can make data difficult to interpret. Taubes instead points to these anomalies as evidence of flawed or incomplete theories, and suggests that isolated populations (outliers) such as the Inuit and Maasai tribes actually help the most in explaining diet-related health patterns.

Taubes argues extensively (sometimes a bit heavy-handedly) against lazy scientific thinking that relies too heavily on conventional wisdom and the appeal of simple ideas. This point is a major theme of the book and is exemplified by chapter 2, “The Inadequacy of Lesser Evidence.” He goes to great lengths to explain how our tendency not to scrutinize established theories breeds scientific closed-mindedness and can perpetuate flawed ideas for decades.

Ultimately Taubes uses this argument to directly challenge one of the most prevailing health theories in Western civilization: the cholesterol–heart disease hypothesis.

Taubes provides hundreds of pages of data and analysis to make the point that total cholesterol is not a good predictor of heart disease or mortality. Specifically LDL cholesterol is only loosely associated with heart disease (at best) and HDL cholesterol (the higher the better) is a much better indication of vascular health. (Read more: How To Raise Your HDL Cholesterol)

Once this basic premise of health is thrown into question, Taubes carries you through the logic of why a high-fat diet cannot be responsible for heart disease (remember the Inuit) and instead presents why quickly digesting carbohydrates are the most likely culprit.

Fundamental to this argument is the tie between heart disease and type 2 diabetes (along with other “disease of civilization” or metabolic syndrome), which are both inextricably linked to carbohydrate consumption. The logical conclusion from his analysis is that all calories are not created equal, despite what we are told daily by the nutrition community and the media. Understanding the logic behind this argument can fundamentally change the way you approach food and is the best reason to read Good Calories, Bad Calories.

Despite this, Taubes’ book is rarely the first I recommend to people who come to me for nutrition advice. There are a few reasons for this, but the main one is that Good Calories, Bad Calories is not an easy read. I’m a scientist and nutrition data junkie, and this book still took me months to get through (I normally read 4-5 per month). For your average eater, a book like this can quickly become a burden and many people will give up before getting to the good part (about half way through it starts to pick up substantially).

In the first few chapters I was put off by the book’s almost defensive tone. A large part of the first section is dedicated to discrediting the character of a pioneering scientist and father of the dietary fat–heart disease hypothesis, Ancel Keyes. Presumably this depiction is intended as background so the reader understands why Keyes so aggressively disseminates a theory that isn’t fully proven. However, I found the extensive character attack unbecoming for a book espousing science and experimental data, and it seemed unnecessary.

Another reason I resist recommending this book as nutrition advice is that it doesn’t offer much in the way of actual advice. Taubes certainly provides compelling evidence that carbohydrates are best avoided and that dietary fat is safer than presumed, but how much of this knowledge can be translated directly to daily life isn’t clear. For practical advice, I prefer Michael Pollan’s In Defense of Food (based largely on the same data).

Scientifically I also have a few issues with Good Calories, Bad Calories. First, the vast majority of the experiments Taubes cites are early diet studies, many from the turn of the century. While these experiments are clearly important, most of them do not reflect long-term (more than 6 months), real life dietary habits. These studies were also almost entirely dependent upon self-reported dietary intake, which is known to be quite inaccurate.

Much of Taubes’ argument about calories is based on the premise that overweight people eat the same amount or less than lean people. This was once thought to be the case, but recently more thorough studies have shown that overweight and obese people do indeed eat more. The problem is that all people (both lean and obese) are poor judges of food intake, and this discrepancy is largest with the biggest meals consumed. This means people who eat the largest meals tend to underestimate their calories the most, and meal size is correlated with body weight.

This does not mean that I disagree entirely with Taubes’ theory on calories. I was more convinced by the rodent studies he presented where dietary intake was tightly controlled and measured. In some of these, obese animals did seem to eat the same or less than leaner animals (always be careful reading too much into rodent data). Interestingly, the difference in body weight was always accounted for by differences in physical activity, a point I find extremely fascinating.

Since mice obviously do not exercise for the purpose of fitting into skinny jeans, the activity differences observed between obese and lean mice is clearly a fundamental change in metabolism (balance of energy use and intake). If this is true and can be manipulated by diet composition rather than voluntary exercise (which causes overeating), as Taubes suggests, this has tremendous implications for treating obesity and disease through selective diets and metabolic manipulation. I think Taubes makes a strong case for this and it is a point that should be taken very seriously by the scientific community.

My final issue with the book is how the data was presented to seemingly support a diet of almost entirely meat and animal products. While Taubes does not come out directly and say “the healthiest diet is 100% meat,” people without a knack for thinking like a scientist can easily come away with this impression (I’ve seen it).

[note: My guess is this is why I get so many emails from people asking me to help them choose between this book and The China Study (click for review), which both come off as scientific but also as diametric opposites. Personally I do not see a huge conflict between the data presented in the two books, but see it as an issue of interpretation. On this point, my vote goes to Taubes for his superior logic and reasoning.]

My own interpretation of the data presented in this book, however, is not that all carbohydrates are the enemy, but rather that quickly digesting (processed) carbs are the real problem. Taubes never refutes this as far as I could tell, though he does glorify meat-based diets (again remember the Inuit) as the best for optimal nutrition, while belittling the case for a balanced diet. But there is an important difference between saying “meat is good” and “all plants are bad,” which he never directly asserts.

Yet many people still take from this book that a protein and fat-based diet is the healthiest option, which is a flawed interpretation. Vegan diets with no animal products whatsoever can be perfectly healthy, as can largely meat-based diets, and that both are perfectly legitimate is a point that is easily forgotten by the end of Good Calories, Bad Calories.

But while the value of eating plants is an important question for the practical implications of Taubes’ theory of calories, it is not fundamental it.

Summary

Taubes’ meticulous research and overly-thorough analysis represent both the strengths and weaknesses of this book. His case for the role of metabolism in health and obesity, and against the dogma that “a calorie is a calorie” is a tremendous contribution to the field of nutrition. However, this depth can make Good Calories, Bad Calories cumbersome and difficult to read.

Final Grade: A

What did you think of Good Calories, Bad Calories?


You may also enjoy:

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For The Love of Food

by | Jul 3, 2009
For The Love of Food

For The Love of Food

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

There are a ton of interesting articles and news stories out this week, and unfortunately I did not have room here to include a favorite recipe. See below for instructions on how to find a comprehensive list of my reading recommendations.

There are some heavy topics here, but all are worthy of your full attention. For balance, I posted several contradictory articles to make it clear that these issues are not simple and clear cut. Anyone who claims otherwise is not thinking hard enough.

If you would like to see more of my favorite articles each week or just don’t want to wait until Friday, be sure to follow me on Twitter (@summertomato) or the Summer Tomato Facebook fan page. For complete reading lists join me on the social bookmarking sites StumbleUpon and Delicious, and share with me your favorites as well.

Submissions of your own best food and health articles are also welcome, just drop me an email using the contact form. I am currently accepting guest posts at Summer Tomato for any healthy eating and exercise tips.

For The Love of Food

  • You. Need. Fat. <<I love Michelle’s (@MPfennighaus) perspective on dietary fat in this article. Just this week I’ve fielded a ton of questions and confusion about fat. I love oils, and so should you. (The Daily Balance)
  • Eating Animal Fat May Lead to Pancreatic Cancer <<Just in case you were thinking about going crazy Atkins-style after that last article, remember that not all the news is good about certain kinds of fat. This study just shows an association (not causation) of animal fat and pancreatic cancer, but moderation is usually a good idea. (HealthDay)
  • Horizon organics alert: here comes “natural” <<B.S. of the week Seems like Dean Foods is bent on ruining all the biggest organic products. First Silk Soy Milk, now Horizon. Apparently they want to charge you organic prices for foods that aren’t certified organic (aka conventional). Don’t fall for it. (via @marionnestle at Food Politics)
  • This just in: Vegetarian diets are fine <<Looks like the American Dietetics Association has finally issued a bill of approval on vegetarian diets. Not sure what took them so long. Personally I don’t have much of an opinion on the vegetarian thing. Sure it can* be healthier than a typical Western diet (*see next 2 articles), but if health is your concern you have more options as an omnivore. No matter what food religion you subscribe to, vegetables are the cornerstone of any healthy diet. (Los Angeles Times)
  • How High Carbohydrate Foods Can Raise Risk For Heart Problems <<Yes, refined carbohydrates are the real culprit in heart disease, not fat. (ScienceDaily)
  • Metabolic Syndrome May Make Breast Cancer More Likely <<Metabolic syndrome, also caused by carbohydrates, increases risk for breast cancer. (HealthDay)
  • Dear Mark: Freezer Essentials <<Those of you living in states that aren’t California may want to start stocking your freezer now, before your farmers markets close up for the winter. Mark Sisson offers some tips on how to make that dream a reality. (Mark’s Daily Apple)
  • Don’t be Fooled by Healthy Food Imposters <<I pick on Diets In Review a lot for being completely full of crap, but I like to give credit where credit is due. Finally some good advice about fake health food from an otherwise irresponsible publication. (Diets In Review)
  • It’s Time to Learn From Frogs <<One of the most important articles I’ve read in weeks. This is a fantastic piece in the New York Times about why we should stop being naive about the impact of environmental toxins (especially endocrine disruptors) on our lives.
  • Soy isn’t affecting men’s hormone levels…but something is <<Another important piece on the impact of hormones on human development. Looks like soy isn’t the problem some people (not me) thought it was. (Nutrition Data)

What great articles did you read or write this week? Leave your links in the comments.

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How To Get Started Eating Healthy: Foods To Avoid

by | Apr 22, 2009
Junk Food

Junk Food

What truly liberated me from worrying about food all the time was shifting my thoughts and fears away from things I couldn’t or shouldn’t eat and instead focusing on delicious foods–foods I love–that also make me healthy. Changing my relationship with food in this way turned it from something that caused me anxiety to something that brought me pleasure.

One unexpected benefit of choosing healthy, tasty foods over bland diet foods was that many of my old cravings for sugary, unhealthy fare disappeared. While I have not found a clear scientific explanation for this, it stands to reason that a nourished body would be less prone to strong feelings of need toward certain foods. I was amazed how powerful it can be to focus on health instead of dieting. These days, really unhealthy foods barely even tempt me.

(This post is the final post of the series How To Get Started Eating Healthy. Part one is Stock Your Pantry, part two is Essential Groceries, part three is Seasonal Shopping, part four is Stock Your Freezer and part five is Balanced Meals. Get future posts by signing up for email or RSS updates–always free of cost and spam.)

Upgrading your healthstyle will go far in helping you overcome your cravings, but as I much as I would love to tell you that you can eat any foods you want in any quantities you want, we all know this is not true. While you are focusing on eating more of the foods you love there are also foods that are generally worth avoiding as part as your daily healthstyle.

There is room for anything in a healthy life, but here are some foods that DO NOT promote health and can lead to weight gain:

  • Sugar In any form, sugar wreaks havoc on your health and metabolism. Two keys to protecting yourself from sugar damage are quantity and timing. Do not eat too much sugar at once (stick to small desserts) and do not eat sugar very frequently. I try to limit real desserts to once or twice per week (max) and satisfy all other sweets cravings with fruit. Eating whole grains is particularly effective at reducing sugar cravings.
  • Refined flour Processed grains (all flour) are almost as bad as sugar in their effect on your metabolism. In fact, your body processes them exactly the same way. Generally look for alternatives to breads, pastas and other foods made with flour. Instead focus on getting carbohydrates from intact whole grains. Try to limit refined flour foods to less than once per day. If you are actively trying to lose weight, I would make an effort to cut these out completely.
  • Trans fat Twenty years ago scientists believed they had solved the problem of saturated fat by replacing it with an artificial solid fat made from plants. It turned out these processed fats, trans-fats, are one of the most dangerous foods you can put into your body. Not only do they raise your “bad” LDL cholesterol, they also contribute to lowering your “good” HDL cholesterol–a double whammy for your health. No amount of trans-fat is considered safe in the diet (the data is striking), and you should avoid these processed fats completely. Better to eat foods made with real butter. Better yet, choose healthy fats from vegetable sources like coconut oil, olive oil and canola oil.
  • Anything processed It is worth emphasizing that nothing processed has ever proven to be healthier for you than real whole foods–even foods with fantastic health claims on the package. In fact, as Michael Pollan points out in his book In Defense of Food: An Eater’s Manifesto, a health claim on a package is a pretty good sign that a food is bad for you. There are no stickers for “Whole Grain” or “Low Carb” on your vegetables, and those are what you should be eating.
  • Red meat As I discussed earlier this week, red meat is probably not good for you. Some people argue that it is really bad for you, and some people think it is not so bad. It appears to not be quite as bad as processed foods, but there are plenty of compelling reasons to limit how much red meat you eat. For myself personally, cancer is a bigger fear than heart disease. But there is also some data that saturated fat plays a role in insulin resistance. I recommend less than one (4 oz) serving of red meat per week. The same can be said about poultry with skin.

I do not recommend completely eliminating foods you love–even if they are bad for you–because this is not something you can maintain forever and it strips some of the joy from life. Instead I suggest trying a few customizable strategies to be sure that the less healthy foods you love bring you happiness, but do not damage your body:

  • Reduce, Don’t Eliminate Simply being aware of how often you eat these foods and trying to stick to the guidelines above can drastically improve your healthstyle. If you currently eat a lot of sugar, processed foods or red meat, do not attempt to completely overhaul your diet overnight. Make changes gradually or it will be very difficult to make them permanent.
  • Be Picky When you first start to upgrade your healthstyle, identify foods you can do without and those you can’t live without. Some changes will be easier for some people, while others are nearly impossible. Focus on the easier changes and do not beat yourself up over things that are difficult for you. Every little change you make will add up to a healthier you.
  • Set Up Simple Rules It is often hard to keep track of everything you do or do not eat. A food journal or Twitter can help with this, but the simpler your healthstyle the better. Setting up simple, easy to remember rules for yourself can help you make healthy changes. The guidelines above are a great place to start. For example, if you decide in advance you can only have one dessert per week, you can be sure that the one you choose is well worth the wait. Use simple rules to both increase your good habits and decrease your bad ones. Experiment to find simple rules that work for you. For example, if you love to eat pizza make a deal with yourself that if you have it you must have a big pile greens on the side–this may also help you eat one less piece.

Please share with us the strategies and rules you use to upgrade your healthstyle!

This is the final post in the series How To Get Started Eating Healthy. Much thanks to those of you have shared your tips and insights in the comments so far. Summer Tomato will continue to build upon these ideas and help make it easier for you to upgrade your healthstyle. If you have specific questions, concerns or even an idea for a future post please submit them in the Ask Me section.

Read more How To Get Started Eating Healthy:

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Should I Buy Whole Grain Pasta?

by | Jan 19, 2009
Pasta

Pasta

Is whole grain pasta really better for you than regular pasta? Recently I featured pasta puttanesca greened up with a little kale in the sauce. When one reader made this recipe at home, he opted to use whole grain pasta instead (I used a regular rigatoni).

But if I care about health so much why didn’t I use whole grain pasta originally?

You probably already know that I health-heartedly support the regular consumption of whole grains. But I also hold that there is a huge difference between intact grains and processed whole grains. So yes, brown rice is better for you than white rice, but pasta is different.

Noodles are made of dough and are therefore processed no matter what. For this reason they will never be a pinnacle of health food, but that does not mean that there can’t be a place for them in your diet. Italians eat pasta almost every day, and most of them are healthier than us. The important thing to think about when you are eating pasta–any pasta–is quantity.

So to answer the question, is whole grain pasta better than regular pasta? Maybe a little. But because I do not eat pasta very often, and because when I do eat pasta I eat a normal (aka small) portion, I always buy what I think will taste the best with meal. And for me, that is usually handmade fresh pasta (the soft refrigerated kind), not the whole grain stuff.

If you do not mind the taste of whole grain pasta, go ahead and buy it. It might be slightly better for you than the other kind. But the impact of whole grain pasta on your overall health is really small, so this is not a question to get hung up on.

Want a healthier Italian meal? Add more vegetables.

What is your opinion on pasta and health?

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