Fructose: friend or foe?

Q. I've been reading conflicting information about fructose.  Is it low-glycemic index or not, a good idea for diabetics or not?  I'm concerned because there's diabetes in my family.  There's fructose added to breakfast cereals and my favorite low-fat frozen yogurt.  If I'm eliminating foods with high-fructose corn syrup from my diet, is some fructose from these sources OK?  What about the powdered fructose sold from the grocery store?

A. Fructose does have a lower glycemic index than regular table sugar, meaning that it causes less of a rise in blood sugar. That's because fructose is not absorbed into the blood stream like glucose but is processed in the liver instead. Note that fructose is not calorie-free, however. It contains the same number of calories as regular sugar.

Fructose is found naturally in many foods, such as fruit. It's also widely used in food manufacturing--both in products for diabetics as well as mainstream foods. Regular table sugar is 50% fructose, similar to the amount found in high-fructose corn syrup.

I think there are a lot of benefits to cutting back on highly-processed, sweetened foods and beverages--regardless of whether they are sweetened with fructose, table sugar, high fructose corn syrup, or even artificial sweeteners. Regardless of the relative merits of the various sweeteners, these foods usually don't have a whole lot to offer nutritionally, and tend to crowd more nutritious foods out of the diet.

Whether you have diabetes or not (or perhaps a predisposition to it), I think a diet based on whole, unprocessed foods--such as fruits, vegetables, whole grains like oatmeal and brown rice, nuts, seeds, legumes, healthy oils like olive oil, and lean meat, eggs, and dairy if you desire--is ideal. If these foods are the bulk of your diet, a small amount of added sugar (or fructose) is not likely to cause problems.

Another log on the low-carb fire

The debate rages on:  Since the dawn of low-carb dieting back in the 70s, experts have worried that a low-carb, high-fat diet, such as that promoted by the late Dr. Atkins, would increase your risk of heart disease. Proponents of low-carb dieting insist that carbs, not fats, are the true culprit in heart disease.  Over the years, numerous studies have provided evidence to support both arguments--without leading to any real resolution or consensus.

This week, a new study published in the Journal of the American Dietetic Association adds another log to the fire.  Researchers at the University of Maryland in Baltimore compared the maintenance phases of three popular diets: Ornish (extremely low fat), Atkins (extremely low carb), and South Beach (moderate "smart" carbs,  moderate healthy fats). Among the findings: both Ornish and South Beach reduced LDL cholesterol levels, while the Atkins increased LDL cholesterol.

What happens next is fairly predictable: Those who believe that a diet high in fat (particularly saturated fat) is unhealthy will no doubt seize on this latest evidence as more proof.  Those convinced that low-carb is the way to go will raise questions about the study's design and validity.

The difference between weight loss and weight maintenance

It's interesting that this study focused on the maintenance phase rather than the weight loss phase of these popular diets.  The beneficial effects of a low-carb diet on heart disease risk factors have mostly been observed during weight loss.  It's possible that any negative impact of the diet on heart health risks may be masked by the enormously beneficial impact of losing weight on those same factors. 

There's no doubt that low carb works for weight loss--and for some people it's the only thing that works.  But I've never been entirely comfortable with the extremely low carb diet as a long-term approach.  I'm not a big fan of the extremely low-fat diet over the long haul, either.  Diets that are extremely high or low in one macronutrient seem much more likely to cause problems caused by defiencies and/or excesses. 

Quality versus quantity

I also think that paying attention to the quality of carbohydrates (in terms of their glycemic impact or effect on blood sugar) is at least as important as regulating the quantity.  A low-carb diet restricts all carbohydrates.  Cutting out high-glycemic refined carbs like sweets and baked goods undoubtedly has a positive effect on heart health. But I'm not sure there's much to gain by restricting low-glycemic carbs like fruits and vegetables. In fact, there is much to lose by eliminating these nutrient-dense foods.

By the same token, low-fat diets cut way back on all fats, including healthy fats that have been shown to be beneficial for both heart health and weight loss. Low fat diets are also typically less palatable and less satiating, which makes them poor candidates for long-term success.

I guess I'm revealing my bias: I favor a balanced diet with proteins, (healthy) fats, and (low-glycemic) carbs in roughly equal proportions.  Ultimately, though, I think it's unwise for us to cite ANY single dietary approach as best for EVERY individual.

Your take?

Overweight kids: Researchers claim they're not eating enough

Interesting study in this month's Journal of the American Dietetic Association. Researchers analyzed the diets and health stats of low-income kids. The kids' diets were very high in fat and sugar, and low in whole foods and important nutrients like calcium, magnesium, phosphorus, and potassium.

A third of the kids were obese. But, surprisingly, when researchers analyzed their diets, they concluded that 44% weren't eating enough calories. Researcher Roberto Trevino offers the following intepretation:

"The problem is not that they're eating too much. It's that they're lacking nutrients that are important for metabolism to burn off fat and sugar."

The mainstream press seems to buy this notion, as evidenced by this headline in the San Antionio Express News: "Heavy Kids Aren't Over-Eating."  (Despite the misleading headline, this story actually gives a very good and balanced summary of the study.)

Frankly, I don't buy Trevino's explanation.  Calcium, magnesium, and potassium are certainly essential nutrients and "important for metabolism" in the most general sense. But they don't specifically "burn off fat and sugar."  That sounds a little too much like those miracle weight loss supplements sold on late-night infomercials. 

Can't you just hear it now: These miracle nutrients turn your body into a fat-burning machine!

No, obviously, if these kids were overweight, they were eating more calories than they needed.  I think the true explanation is two-fold:

1. The kids were sedentary and therefore needed fewer calories than researchers estimated that healthy kids would need to grow.

2. The kids ate more than they told the researchers they did. (This is typical of self-reported food intake.)

What this study clearly shows that low-income kids are eating poorly and suffering because of it. Not only are a third of them obese, but 7% are already at risk of diabetes. But to suggest--as these researchers seem to be suggesting--that they're eating too few calories and getting fat anyway because of a lack of minerals which "burn off fat and sugar" seems ridiculous and even dangerous to me.

What do you think?

Vitamin D: Now I'm a believer

One of the most electrifying sessions I attended at Andrew Weil's Nutrition and Health Conference in April was one given by Dr. Michael Holick on Vitamin D.  Dr Holick is a well-known, even notorious, name in nutrition research circles. He's been insisting for years that vitamin D deficiency is far more wide-spread and dangerous than anyone realizes and he has a reputation (which he himself promotes!) of being a bit of a kook. 

A few years ago, he was famously booted from the Boston University dermatology faculty for making heretical statements about the benefits of moderate UV exposure (which stimulates the production of vitamin D in the skin) and has been chided and derided by the dermatology establishment ever since.

I thought I had a pretty good idea of what to expect from Holick's presentation; it would be all about the miraculous powers of vitamin D and the dire consequences of deficiency.  I tend to take these sort of Wonder Nutrient presentations with a grain of salt.  When you spend your whole life researching a single compound--like many of these researchers do, I think you can start to lose your sense of perspective. As the old saying goes: When you're holding a hammer, everything starts to look like a nail.

The evidence is always reasonably compelling. And by the end of every Wonder Nutrient presentation, you find yourself thinking, I really should start taking that, and I should probably start recommending it to my patients, too. The problem is that after a few dozen of these presentations, you (and your patients) have a list of 40 nutrients that you "need" to be taking.

It's probably a backlash against too many Wonder Nutrients but, as many of you know, I'm not all that big on dietary supplements. Whenever possible, I think it's better to meet your nutritional needs with actual foods. I myself take very few supplements.  And I have become immune to the persuasive power of Wonder Nutrient lectures.

And yet, after hearing Dr. Holick's presentation, I literally stopped on my way back to the hotel to buy a bottle of vitamin D (1000IU).

Is microwaving safe?

Q. Is it safe to microwave food? Does it affect the nutrient content of foods?

A. This question came up at the Nutrition and Health conference I recently attended, and it's especially  timely given our recent discussions about how to reduce energy use in the kitchen.  Microwaving is a very energy efficient way of cooking foods. But many people have concerns about the effect of microwave radiation on foods.

First off, no radiation remains in the food (or in the oven) following microwaving. As long as your microwave oven seals properly, radiation is not a concern. (If you're unsure, you can buy an inexpensive radiation leakage detector to test the integrity of your seal.)

But what about the nutritional value? In fact, the nutrient content of microwaved foods may be slightly higher than that of conventionally-cooked foods, because the cooking time is vastly reduced and less water is used. (Long cooking times degrades nutrients and exposure to water leaches vitamins and minerals from foods.)

There have been some concerns about the effects of microwaving on protein foods, particularly that microwaves denature or otherwise alter protein configuration.  All cooking denatures proteins and although I've certainly heard a lot of rumors, I haven't been able to find any conclusive evidence that normal microwaving alters proteins in a way that would be dangerous. 

The main danger associated with microwaving foods is the absorption of dangerous compounds from plastic containers or plastic wrap that comes into contact with the food being cooked. This truly is a concern, even for containers or wraps that are labeled "microwave safe."  Use only glass or ceramic containers to microwave foods.

Microwaving can't always match the results of baking or roasting foods, in terms of taste or texture. For many tasks, however, such as heating liquids, cooking frozen vegetables, or reheating leftovers, it's perfectly acceptable.

The bottom line? Microwaving offers a quick and energy-efficient way to cook or reheat foods while minimizing nutrient loss. Just keep in mind 3 safey tips:

1. Never use plastic wrap or containers. Use only glass or ceramic to microwave.
2. Cover cooking dishes and stir foods during cooking to ensure even heating.
3. Avoid over-cooking foods.

Did you know this? I didn't!

Still at Dr. Weil's Nutrition and Health Conference here in Phoenix. Yesterday I learned something new at a session on glycemic response presented by Dr. Louise Gagne.  Most of the lecture covered familiar territory...how refined carbohydrates like white bread and sweets cause a sharp rise in blood sugar, the negative effects of blood sugar spikes on the body, and how to choose low glycemic foods for better health. Dr. Gagne had a list of tips for reducing the glycemic load of your diet:

1. Avoid foods made with white flour and sugar.

2. Eat protein and/or fat with carbohydrates to slow the digestion.

3. Eat foods high in soluble fiber. (See also this recent post.)

4. In any given category of foods, eat the ones with a lower glycemic load. (You can find the estimated glycemic load of any food here on Nutrition Data, or search for foods by eGL using the Food Category Explorer.

But here's one I didn't know:

5. Drizzle lemon or vinegar over some part of the meal.  Apparently, these acids can significantly slow the uptake of sugars in the foods you eat them with.

More to come...

Is a varied diet over-rated?

I attended a very interesting session this morning at the 5th Nutrition and Health Conference that I'm attending here in Phoenix, AZ. Dr. Daphne Miller, a professor of medicine at University of California at San Francisco, gave a presentation on her new book, The Jungle Effect.

Over the past ten years, scientists have spent a lot of energy investigating the world's healthiest and longest-lived populations, trying to figure out what they are doing right. Why do they live so much longer and have vastly lower rates of cancer, heart disease, diabetes, and other diseases than Western countries?  We've picked apart and analyzed the traditional diets and lifestyles of Okinawans, Cretans, Icelanders, Cameroons, Pima Indians, and so forth, in an attempt to codify, once and for all, the healthiest diet.

The problem, as Dr. Miller discovered when she travelled to all of these places to see for herself, is that health and longevity are about the only things that these cultures have in common.  The robust Tarahumara Indians, for example, eat a diet of 80% carbohydrates (mostly in the form of starchy vegetables like corn and potatoes!), while the indestructable Cretans get almost 50% of their calories from fat.  Some long-lived cultures eat almost no meat, while the hale and hearty Icelanders eschew vegetables as "animal feed" and eat large quantities of lamb and fish. 

I can't do justice to Dr. Miller's entire argument in this short post (although I highly recommend checking out her new book), but she concludes that traditional diets work chiefly because they are based on the plants and animals that flourish in the local ecosystem, prepared and consumed in a way that has been fine-tuned by generations of trial and error to provide optimal nutrition for those people.

That's not to say that only indigenous people will flourish on a particular traditional diet, says Dr. Miller. If you adopt ANY of these diets, she says, you will likely see an improvement in your health. Conversely, all of these incredibly healthy populations suffer from the "migration effect." When they migrate to Western industrialized nations (or McDonalds inevitably sets up shop in their small village), within a few years, they invariably begin to show the same sorts of degenerative conditions that are routine in Westerners.

Despite the staggering differences between various, apparently "successful" indigenous diets, Dr. Miller has attempted to find the common threads. Among the key concepts she identifies: consumption of native grains, fermented foods, spices, and communal (unhurried) eating. But the differences still seem to loom larger than the commonalities.

A unifying concept that Dr. Miller didn't mention is that all indigenous diets are composed of a relatively small list of foods. In most cases, about two dozen foods provide 95% of the calories--in some cases,  fewer than a dozen! Compare this with the tens of thousands of food products we are confronted with at the grocery store. Hundreds of kinds of produce from every climate inn the world. Dozens of kinds of grains.  Scores of protein sources.  We think nothing of eating Indian food on Monday, Chinese on Tuesday, sushi on Wednesday, Latin-American on Thursday and Greek on Friday. And this got me thinking: Is a varied diet over-rated?

As a nutritionist, I myself frequently cite the advantages of a varied diet. First and foremost, you increase the range of nutrients you consume by eating a wide variety of foods, especially whole foods.  Secondarily, you limit your exposure to toxins (natural or unnatural) that might be present in certain foods.  It's a cover-all-your-bases and hedge-your-bets sort of approach and one that always made sense to me.

On the other hand, some of these indigenous cultures remain in enviably good health on a diet of two or three vegetables, one source of protein and one or two kinds of grain.  It makes you think, doesn't it? For one thing, it is a fact that we tend to eat more when confronted with a large variety of foods than we do when we eat just one or two things at a meal. (Think of your behavior at buffets.)

I'm hoping to have a chance to catch Dr. Miller later in the conference to get her take on this (and I've got to run to the next session now), but in the meantime, what do you think?  Could we improve our diets just by making them simpler?

If you had to choose just two dozen foods to make up your entire diet for a week, what would they be?

Greetings from the 5th Annual Nutrition and Health Conference

I'm writing to you from sunny Phoenix, where I'm attending the 5th Annual Nutrition and Health Conference, hosted by Dr. Andrew Weil and the Program in Integrative Medicine at the University of Arizona.

The sessions I've attended so far have been full of great, practical insights into how we can make our diets healthier. I can't wait to to share this information with you in more detail! I only have a few minutes before the next session begins but wanted to dash off a quick post with some of the highlights so far.

In the opening session this morning, Dr. Weil set the stage for the rest of the conference with some general observations about diet and the role it plays in our long-term health.  A few nuggets:

On fat: Low-fat diets (less than 20%) are not only unsatisfying and difficult to stick to, but they don't appear to be necessary for good health.  Dr. Weil argues (and I agree) that diet containing 30 to 40 percent of calories from fats is perfectly healthy. Of course, what kind of fats is important. Most of the fat in your diet should come from monounsaturated sources, such as extra virgin olive oil or canola oil.

At the same time, Dr. Weil points out that there's no reason to be paranoid about saturated fat:

"You need to limit your intake of saturated fats but you don't need to be afraid of them. Set a budget for your saturated fat consumption [I recommend 10% of calories--MR] and then decide how you want to spend it. If you love butter or ice cream, spend your saturated fat budget on those foods. Personally, I love cheese, so that's what I choose to spend my saturated fat calories on."

ND Tip: you can analyze the fat content of your diet using our Caloric Ratio Pyramid and/or track your saturated fat "budget" using our diet tracking tools.

On protein: We've been trained to think in terms of "good" and "bad" carbs and fats but we tend to think of proteins as all "good" calories.  The problem with protein foods, says Dr. Weil, is what often comes along with them.  Conventionally-raised livestock may contain antibiotics, hormones, pesticide residues; fish may contain mercury, PCBs, and other contaminants. 

Most of us could get along on a lot less protein than we are currently eating. Dr. Weil recommends  getting 10 to 20% of your calories from protein-- and much of it from vegetarian sources.  Those with diminished kidney function may want to eat an even lower-protein diet to save wear and tear on the kideys:

"One thing I see in traditional medicine is that we wait too long before we tell people with kidney disease to start restricting protein. We wait until they are in kidney failure.  If we started them on a low-protein diet ten years earlier, at the first signs of declining kidney function, we could probably avoid or at least delay the onset of kidney failure."

On essential fatty acids and balance:  With all the emphasis on getting more omega-3 fatty acids, we've started to think of omega-6 fatty acids as "bad" nutrients. Dr. Weil reminds us that omega-6 fatty acids are essential for good health!  The problem is one of balance. 

"The body is designed to function in a state of dynamic tension--between forces that push and forces that pull. We need to support both forces in equal measure to remain healthy."

And consider this: The amount of omega-3 you need to consume to keep your body in balance is directly related to the amount of omega-6 in your diet, Weil points out.

"It takes very little fish oil to balance the blood chemistry of someone eating a diet that is very low in omega-6 fatty acids. But for most Westerners, who consume a huge amount of omega-6 in their diets, it takes an enormous amount of fish oil to accomplish the same goal."

ND Tip: you'll find the omega-3 and omega-6 content of foods, recipes, and meal plans as part of our complete nutritional analysis.

There was so much more to report, but I'm out of time for the moment. I'll post updates throughout the conference and will also post in greater detail on some of the more interesting research after I get home. Wish you were here!