Mango Vendor in Bangkok

Several readers have asked lately about the impact of fruit–specifically the sugar in fruit–and it’s capacity to cause weight gain and accelerate aging through insulin signaling:

“Do people usually gain weight because of eating fruit and does the sugar in fruit age us?  I just hate to think that I am doing my body harm by eating fruit.”

If this question sounds insane to you, it shouldn’t. It is actually a very reasonable query that was sparked by two Summer Tomato articles, one about saving money while eating healthy and another on calorie restriction, aging and quality of life. In the first article I recommend thinking of fruit as dessert, a treat to be enjoyed once or twice per day. The second article is about the impact of sugar and calories on aging.

Body Weight

The fact is that fruit contains a lot more sugar than other natural foods and in large enough quantities it can contribute to weight gain. But fruit is certainly not bad for you, nor is it worse for your health than anything else in life.

The sugar in fruit contributes calories to your diet, but since you need calories to survive fruit is still a very good choice. The reason is that in addition to sugar (fructose, to be specific) fruit also has vitamins, minerals, antioxidants, fiber and many other things that contribute to health and possibly slow aging.

On the rare occasions when I do make an effort to lose a little weight, however, remembering that fruit should be dessert is something I keep in the back of my mind. I eat fruit every day, but when trying to lose weight I keep it under two servings and always choose whole fruit–avoiding anything blended or juiced. (Drinking calories is usually a bad idea.)

But this healthstyle tactic is not for everyone.

Why?

Unlike most people trying to lose weight, I already have a very healthy diet and fruit is one of the easiest places I can trim calories without feeling deprived. Cutting out things like fat and protein make dieting very difficult because you are always hungry. In my experience reducing unnecessary carbohydrates–especially sugars–is the easiest and healthiest way to lose weight.

But it is essential to remember most people are not overweight because they eat too much fruit and the vast majority of people would benefit from eating more of it.

Aging

The question about whether sugar causes aging is a fascinating one that I am very interested in.

Yes, in most organisms eating sugar has been shown to promote aging, but this has not been proven in humans. Sugar induces aging via the insulin signaling pathway, so therefore any food that increases insulin signaling could theoretically accelerate aging. The problem is that you need insulin to survive–those who cannot produce insulin have a disease called type 1 diabetes.

The good news is that eating a diet that minimizes insulin signaling is also the best way to lose weight and stay healthy, so if you are living a healthy lifestyle (one that includes fruit) you do not need to worry about anything else.

Although fruits have sugar, it is extremely unlikely that they accelerate aging. In fact, most evidence suggests that fruit slows aging because of its high levels of vitamins, minerals and antioxidants.

If anti-aging is your goal, fruit is your friend not your enemy.

For more on insulin signaling, check out my post at MizFit Online, When is a calorie not a calorie.

Conclusion

While fruits contain sugar, they do not pose a special threat to your health goals. Eat and enjoy fruits as a wonderful and delicious part of life.

How much fruit do you eat?

Originally published August 31, 2009.

Tags: calories, fruit, insulin

Photo by yomi955

Cutting processed foods and refined sugars out of your diet is arguably the most important dietary change you can make to improve health and lose weight. But will one slice of birthday cake inevitably tighten your pants and cut your life short?

Not necessarily.

Quality of life is hard to measure, but it certainly involves some balance between good health and hedonistic enjoyment of things that might not be perfectly healthy. The question is how we find this balance for ourselves, and how do we make sure our behavior helps us keep that balance?

The answer, of course, will be different for everyone. Competitive athletes have higher physical demands for maintaining ideal health than, say, a scientist. And I’m not a fan of watering down my favorite foods–especially desserts–with “healthier” ingredients. But there are a few general guidelines that can help the majority of us live a little without constantly fighting the battle of the bulge.

9 Tips For Dealing With Dessert

1. Eat dessert once per week or less

As a general rule I try to keep my dessert consumption to once per week or less (it is often less). A larger person may be able to get away with a bit more, but setting a weekly maximum can help you keep tabs on your sugar consumption. If you are actively trying to lose weight, aiming for once every two weeks or less is ideal.

Sugar is problematic for several reasons. Most of you probably realize by now that excess sugar causes rapid blood sugar and insulin spikes that force extra calories to be stored as fat. Over time these spikes will alter your sensitivity to insulin, negatively impacting your metabolism and risk of type 2 diabetes. Extra insulin signaling is also associated with heart disease, high blood pressure and accelerated aging.

The less refined sugar you eat the better, but assuming most of us aren’t willing to give it up completely it is helpful to have a weekly maximum to keep consumption in a reasonable range.

2. Pick your occasions

Once you decide to budget your sugar consumption, it is time to start choosing your priorities.

Is your weekly group meeting at the office (the one where there’s always doughnuts) really a special occasion? In other words, is that stale chocolate doughnut you wolf down while half asleep really worth the extra workout or skipping dessert with your kids this weekend? Probably not.

If you think about it, there’s a good chance you don’t even enjoy that doughnut as much as you assume you do. And we both know you’ll feel horrible after eating it anyway. So why do you believe that you want it?

When you stop and really think about your food choices, you’ll often find that many of them come from conditioning rather than true preference. But just because 12-year old you liked low-quality sweets doesn’t mean the adult you has to continue eating them.

Save desserts for the times that are really worth it, and realize you aren’t missing much by skipping the Costco brownie bites.

3. Don’t eat dessert alone

Special occasions are moments of celebration you share with people you care about. One of the wonderful things about life is these moments happen all the time. Our weeks and months are perpetually marked by birthdays, weddings, promotions, vacations and a million other reasons to celebrate. Use these special times as cues for when to indulge.

On the other hand, there is nothing particularly special about sitting alone on your couch watching TV. Try to get out of the habit of eating dessert alone, especially if this is something you rely on for comfort. If you just want something sweet, try having a piece of fruit or some herbal tea instead.

I recommend not keeping any pre-made desserts in the house at all. Why torture yourself?

4. Know dessert when you see it

If you’re eating dessert several times a day but only think you are eating it once or twice per week, none of these rules are going to help you maintain your health and physique.

Last week I wrote about the hidden sugars in common foods such as sandwiches, salads and fruit yogurts. There are clearly benefits to eating a salad, but syrupy dressings contribute to your sugar intake whether there is lettuce around or not. Overly sweet non-dessert foods make it more difficult for you to enjoy real indulgences without consequences.

Be aware of the sugar content in the foods you eat and actively try to minimize it in the bulk of your diet (i.e. choose sandwiches without teriyaki or BBQ sauce, salads with savory (not sweet) dressing, cocktails without juice or syrup, and plain yogurt).

If you’re eating healthy and minimizing sugar 90+% of the time, your waist will hardly notice the occasional birthday cupcake.

5. Little indulgences count

Just as you cannot ignore the 27 grams of sugar in Yoplait yogurt, you can’t grab 2 or 3 pieces of candy every afternoon from the bowl in the office without it adding up.

Be aware of the little cheats you make throughout the week and don’t kid yourself about their impact. If you decide that the work day is just too hard to get through without these, that’s fine. But you aren’t doing yourself any favors by pretending they don’t exist. Remember to count them in your mental dessert tally and keep it in mind when you’re looking lustfully at your grandma’s homemade apple pie and wishing you hadn’t had so much sugar this week.

6. Choose quality over quantity

If your goal is to limit your sweets but you don’t want to feel like you’re missing out, make sure your choices emphasize quality over quantity.

A few bites of good quality dark chocolate is infinitely more satisfying than a handful of Hershey’s kisses. Desserts can rack up 25-100 calories per bite. Get the most bang for your buck by picking foods with actual flavor and not just extra sugar and salt.

Hint: This tip should also help you stick to tips #2 and #5.

7. Go splitsies

Half a dessert is 100% better for you than a whole dessert.

If you really really want to try one of those cookies your co-worker has been bragging about for months but have already had your ice cream this week, try taking only half of one. Better yet, find someone to split it with you so you aren’t tempted to finish it. If it’s that good, a few bites should be plenty satisfying.

8. Resist peer pressure

Some people take a special pleasure in encouraging others to do things they know are bad for them. These people also tend to be good at recruiting others to join in their banter.

Be prepared to get nagged occasionally for not wanting to eat foods that aren’t worth it. But if you have decided in advance to stick to desserts you know taste better than what your friends are pushing, it really isn’t that hard to ignore them.

Who’s really missing out here?

9. Use the gym

Despite our best efforts, we all eat too much dessert every now and then. This isn’t good, but it isn’t the end of the world either.

When this happens to me I use it as an opportunity to amp up my workout routine. By far my best runs are on days when we have birthday cake in lab–I feel like I can run for days with all my extra energy.

Your muscles use sugar as fuel, so use it up while you can and give your metabolism a little boost (having a little extra blood sugar and insulin around when you’re exercising can actually improve your metabolism) and prevent those spare calories from being stored as fat.

You’ll probably feel better after working it off too.

How do you deal with dessert in your healthstyle?

Tags: blood sugar, dessert, insulin, insulin sensitivity, sugar

For The Love of Food

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

The interwebs gave us lots of great healthy food tips this week, from an unexpected benefit of eating (and smelling) real, quality food to peeling a mango like a zen master. There is also a great article on DIY packed lunch tips and some good news about beer.

I read many more wonderful articles than I post here each week. If you’d like to see more 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. I’m very active on all these sites and would love to connect with you there. (Note: If you want a follow back on Twitter introduce yourself with an @ message).

Links of the week

• Confused about nutrition? Eat food! <<Marion Nestle elaborates on her position regarding single nutrient science and why we’re better off just eating food. (Food Politics)
• Complex smells make food more filling <<One of the reasons I emphasize real, high-quality foods on this blog is because they are so much more satisfying and contribute profoundly to a better quality of life. A new study suggests that their wonderful smells may be partially responsible. (New Scientist)
• Another perspective on the sodium wars <<I always love to read Monica Reinagel’s perspective on nutrition trends. Here she elaborates on sodium and high blood pressure. (Nutrition Data)
• Beer for the Bones? <<That’s right. The silicon present in some beers may contribute to bone health. I wouldn’t start drinking more to prevent osteoporosis, but it’s nice to fantasize right? (HealthDay)
• The Zen of Peeling a Mango <<It’s mango season, Mangoes are good and healthy, Easy to peel. (Who doesn’t want to start the weekend with a mango haiku?) (ReadyMade)
• A Butcher’s Tips for Avoiding Cuts in the Kitchen <<Safety first. Playing in the kitchen is fun, but it is easy to hurt yourself. Learn to handle a knife safely from the pros. (Lifehacker)
• 8 Foods That Will Hide Your Bad Breath <<I haven’t written much about Valentine’s Day this year, but a little good breath could never hurt anyone. (Dumb Little Man)
• How to cultivate the packed lunch habit & save <<I’m a big fan of lunch, habits and DIY foods. Saving money doesn’t suck either. This article is full of great tips. (Stone Soup)
• You Know About Insulin. And Now, the REST of the Story . . . <<People LOVE to over-simplify health and nutrition. Insulin gets blamed for a lot, and rightly so, but keep in mind there is a lot more going on than just carbs and insulin spikes. (Diabetic Mediterranean Diet Blog)
• Farro & Winter Vegetables Recipe <<I love Amy. I love seasonal vegetables. And for some reason I’ve never cooked with farro. Something is wrong with this story and I think this recipe solves it. (Cooking With Amy)

What inspired you to eat well this week?

Tags: breath, insulin, knives, Lunch, mango, recipe

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?

Tags: aging, calorie restriction, carbs, Cynthia Kenyon, diseases of civilization, glycemic load, insulin, low-carb, protein, refined carbohydrates

Jeff Miller/University of Wisconsin Madison

Last week The New York Times published a story on the life prolonging effects of a low calorie diet in primates. The study in question found that like other organisms (from yeast to worms to mice), rhesus monkeys that eat 30% fewer calories age more slowly and develop fewer diseases than animals on a traditional diet. Those of us who follow the scientific literature on nutrition and aging are not surprised by this at all.

A few days after the story was published The Times published an op-ed questioning the value of the research. Roger Cohen argues that Canto, the healthier monkey, has suffered tremendously as a result of his restricted diet. He contends that it is far better to be fat and happy (and dead?) then thin and miserable.

To me it seems questionable why Cohen believes Canto is unhappy. If he is making his judgment solely on the image above, I must respectfully disagree with his assessment. To me both monkeys appear relatively miserable.

However, Cohen brings up a crucial question about diet and health. How far are we willing to go–how much are we willing to change our diets–in order to extend our lives?

Quality of life is a very important question.

To me one of the most interesting things about calorie restriction is that life extension is only one of many health benefits. Calorie restriction literally slows down the aging process. As a result the animals subject to a limited diet are able to maintain a high level of physical activity into old age. They are also relatively free of age-related diseases including cancer, heart disease, diabetes and neurodegenerative diseases.

Extended life would arguably not be as desirable if these diseases maintained the same progression as they do in those with normal diets. But freedom from these diseases and preserved physical and mental capacities may indeed be worth some dietary alteration.

The next question is how must the diet be changed?

In the monkey experiment, the calorie-restricted group received 30% fewer calories than the control monkeys, who were allowed to eat what they wanted. It is still unknown if a 30% reduction in calories will extend human life in a similar manner, but short-term experiments have indicated that at least some benefits are immediately apparent when calories are limited, such as lower triglycerides, body fat and blood pressure.

Interestingly, however, there may be alternatives to a strict low calorie diet. Cynthia Kenyon, a scientist at UCSF, was the first to show that the key to the life extending properties of calorie restriction is the insulin signaling pathway. A decrease in insulin signaling slows the aging process and extends life.

In the laboratory, organisms like worms, mice and monkeys always receive a uniform diet that has a consistent effect on insulin signaling. But humans do not eat lab food (at least not usually).

Extensive research over the past several decades has made it clear that different foods impact insulin signaling differently in humans. For example, refined carbohydrates have a large, rapid impact on blood sugar, insulin secretion and insulin signaling. By contrast, fat, protein and fiber have next to zero impact on blood sugar and subsequent insulin signaling.

The implication of the diverse human diet is that we are able to alter insulin levels and signaling in our bodies without undergoing severe calorie restriction. Whether or not a diet that promotes less insulin signaling can slow aging in humans is still unknown, but there are many other benefits associated with a diet that lacks refined carbohydrates.

Insulin signaling is not only tied to the aging process, it is also the primary cause of metabolic syndrome–high triglycerides, insulin resistance, hyperinsulinemia, abdominal obesity, low HDL cholesterol and high blood pressure–as well as type 2 diabetes and heart disease.

A diet that improves these symptoms may or may not slow the aging process directly, but it can certainly promotes a higher quality of life by lowering the risk of many debilitating and life threatening diseases.

Going to farmers markets and eating delicious meals isn’t so bad either.

What are your thoughts on health, diet and quality of life?

Tags: caloric restriction, insulin