Daniel S. Frank, MD, PLLC

Battle of the Network Diets

Controversy abounds in the field of dietetics. Be cautious about national recommendations which change, often radically, every few years. In addition, the lay press is full of bizarre fad diets which come and go. Most diets are not subjected to any sort of scientific study, and their "success" is based on book sales, product revenue, or the political maneuvering which brings disparate "national" health groups to an uneasy-and possibly incorrect-consensus. Patients must remember that eating is one of life's great pleasures. Overly restrictive diets which leave you feeling hungry and deprived are doomed to failure because no one, other than perhaps the diet book author, can stay on them.

There are currently three points of view regarding diet, with advocates in each camp at war with one another over the dieters pocketbook.

Low fat diets - as advocated by Dean Ornish and The Pritikin Longevity center aim for a fat intake which is very low, on the order of 10-15%. Ornish adds omega 3 fatty acids (fish oils) and points out that on his diet, patients have regression of coronary artery disease. A very low fat diet is worthy of consideration in patients with established coronary artery disease, but these diets require a great deal of motivation, and patients are unlikely to stay on them long term. They also have not been adequately evaluated in scientific trials. Patients lose weight on the Ornish diet.

Low carbohydrate diets-Atkins is the prototype of this diet-turn the traditional food pyramid on its head. Dieters eat as little carbohydrate as possible and mostly take in protein and fat. Initially, Atkins did not make much of a distinction between saturated and unsaturated fats, but in later years he has correctly promoted the unsaturated fats. Low carbohydrate diets are probably more effective for weight loss than a so-called "prudent diet" which is likely to be advocated by a traditional dietician. Overweight patients with diabetes may do well on a low carbohydrate diet.

Prudent Diet - as recommended by the American Heart Association, and the US Department of Agriculture. These diets recommend lots of carbohydrates and less fat than we currently consume, particularly less saturated fat. This is the famous "food pyramid" with a big layer of carbs at the bottom and a tiny peak of fat at the top. When you read the food labels and look at the percentages, these are the numbers they are referring to. When you go out to dinner and eat a huge plate of pasta with olive oil on it and think you've done your body a favor, you're on this diet.

Mediterranean diet - one study showed that a diet high in fish, fruits, vegetables, whole grains, olive oil, and canola oil, but low in red meat, milk products, and butter dramatically reduced the risk of further heart disease in patients who already had a heart attack. Some patients take supplements of omega-3-fatty acids to try to replicate the beneficial effects of this diet. It would be nice to see some follow up studies to the single one I've noted in the literature. Of interest here is that patients' cholesterol did not go down at all, but their risk of heart disease did. Just because a diet does not lower cholesterol does not mean it should be disregarded. Similarly, a drop in LDL cholesterol (the "bad cholesterol") in the setting of a very extreme diet does not necessarily mean it will be helpful. Patients did not lose weight on this diet.

The following foods are bad on every diet listed: French fries, potato chips, bacon double cheeseburgers (but only the bun is forbidden on Atkins), milk shakes, chocolate cake, chocolate chip cookies, Milanos, white bread, white rice, hot fudge sundaes. The following foods are good on every diet listed: Fish, skinless white meat of chicken, olive and canola oils (in limited quantities on Ornish and Pritikin), most green leafy vegetables.

Dr. Frank's Desert Island Semi-Starvation Diet

People often ask, "Doctor, what should I eat?" I interpret the question, "What diet will give me the longest life and keep me healthy?" Well, that's easy. You should move to a deserted island, forage all day long for nuts and berries, and kill and eat a small animal once in a while. You would have no refined or highly processed carbohydrates, little in the way of animal fat, you would get abundant exercise, and lead a life of chronic, mild starvation. The best scientific evidence says all those things contribute to a long, healthy life.

Obviously, this plan, the "Dr. Frank deserted island semi-starvation diet" is not realistic. And so the challenge is to find a reasonable diet that people can follow that reduces early mortality. The objective is to eat in a way which is not overly punitive to your psyche, but at the same time helps your body stay healthy. Let's set aside weight loss for a moment and focus on selecting the foods associated with a longer life. There are three principal dangers when examining various diets to see if they are healthy.

The diet is unpalatable: Very few people can stay for the long term on a Pritikin-type diet with 0.001% fat, even if it does reduce your cardiovascular disease risk. Diets which are extreme in any fashion are unlikely to be successful over the long haul.

The diet doesn't make you live longer: It is a mistake to focus on a single outcome, such as breast cancer or heart attack. The Okinawan diet, for example, is associated with a very low risk of heart attack, but people in Japan often die of stomach cancer or stroke. What you really want is the lowest overall mortality.

The science behind the diet is unproven: It is very hard to do a randomized trial of food. People in Okinawa live a long time and eat a certain way, but does that mean that if you are 6th generation Norwegian that you can get the same benefit eating Japanese food? Nobody really knows. Cholesterol will fall on an Atkins diet, even with lots of saturated fat, but that doesn't necessarily mean your cardiovascular risk, or your overall mortality is going to be lower. Dietary studies often substitute one outcome, such as total cholesterol, for another, more interesting outcome, such as life expectancy, and there is no guarantee that the substitute outcome is going to be accurate.

Given these concerns, there is some promising data which comes from a recently published study of 22,043 patients in Greece looking at the benefits of the "Mediterranean Diet." There is no single Mediterranean diet. Each of the dozen countries in the region has a slightly different way of eating. This study looked specifically at patients in Greece. People were ranked as to how closely they followed a "Mediterranean" diet on a scale from 0-9. For every two points a person moved up, following the diet more closely, the risk of death decreased by 25%.

This seems like an amazing result. The next obvious question is which part of the Mediterranean diet contributes to the lowered risk of death? If you're like me, you would guess it was the olive oil, but in fact, no one single food item, such as olive oil, accounted for the differences in mortality. It was the overall increased consumption of vegetables, legumes, fruits and nuts, whole gains, and monounsaturated fats (canola oil, olive oil) which made the difference.

Similarly, there was not one "bad food," but the overall consumption of diary products, meat, potatoes, eggs, and saturated fat which made matters worse. The main challenge in interpreting a study like this is that it is not really an "experiment." It is not a randomized trial of various diets. Other factors could have partly accounted for the differences in mortality.

For example, the study also showed that having more years of education reduced mortality by the same amount as following the Mediterranean diet, but no one seriously believes that going to college causes you to live longer, except that it may reinforce a lifelong habit of alcohol consumption. The problem is that "naturally healthy" people who are born lucky also tend to be the same ones who eat right, exercise, don't smoke, and take care of themselves.

Researchers try to account for all these differences and use statistics to calculate how much advantage in survival is due to the diet as opposed to these other factors, but making those adjustments is a very inexact science and the medical literature is full of discredited studies that miscalculated such effects. How could we know for sure if the Mediterranean diet makes you live longer? You would need to take 2,000 people, and by the random toss of a coin, give half of them the Mediterranean diet and the other half a more traditional Western diet. You would have to prevent them from "cheating" and follow them for 5 - 10 years and then compare the groups. It would be a difficult study to do.

One valuable aspect of this study, however, is that it looked directly at overall mortality. This wasn't a study that just showed changes in cholesterol or blood pressure, people following the diet actually lived longer. Patients on Mediterranean diets tend not to lose weight, as they do on Atkins, for example. A patient on Atkins might be thinner, and might even have a lower cholesterol, but a traditional Atkins diet is high in saturated fat and I suspect that overall mortality would be worse on Atkins, despite having better "numbers" although this is untested. Suppose the Mediterranean diet is good for Greeks, then is it good for Asians or Native Americans?

Perhaps the key is to follow the diet of your ancestors, trusting in Darwinian evolution to have previously fine-tuned your body to do best with the foods it has been exposed to longest. If that is the case, then perhaps thousands of years from now, people will require a Big Mac and fries on a regular basis. Heaven forbid they should adopt a low calorie, low saturated fat diet!

Why We Love Chocolate

After years of research, the scientific conclusion is that we like chocolate because it tastes good. Perhaps this seems like an oversimplification. What about the methylxanthines? The phenylethylamine? The tryptophan precursors? Don’t they elevate mood and explain chocolate’s addictive qualities?

Well, researchers have looked at all these chemical elements and concluded that it is the good taste—and nothing else—which keeps us coming back for more. Consider this experiment: take a group of chocoholics and give half of them a chocolate bar, which will make them happy of course, but give the other half the same amount of chocolate in a capsule of cocoa powder which they will swallow but don’t enjoy. What happens? Only the people eating the chocolate bar were happy.

If you feed these same people white chocolate, which may taste good but actually contains no chocolate, it was still more satisfying that the cocoa powder capsules.

Many foods have identical chemicals as chocolate, but don’t elevate mood. For example, cheddar cheese has ten times as much phenylethylamine (the “love” chemical) as chocolate, but you usually don’t find people munching on cheese balls at two in the morning. Also, the phenylethylamine is mostly broken down after eating and does not reach the brain. In fact, it is the positive sensory experience, the good taste of chocolate, that makes people feel warm and happy inside.

Eating good foods causes the releases of endorphins which are pleasure chemicals in the brain. Why is chocolate so uniquely potent at releasing endorphins? Because it tastes so good! But is chocolate harmful? All by itself, no. Chocolate does not cause acne, and it is no more likely to make people overweight than any other food. The so-called “caffeine” content, actually a caffeine related chemical called theobromide, has little of the caffeine “kick” to it.

The problem is that to make chocolate palatable it needs to be mixed with a huge amount of refined sugar and fat. My advice to patients is “everything in moderation, including moderation.” You have to splurge somewhere in life, and chocolate has a far better safety profile than alcohol, cigarettes, cocaine, and sky diving.