Crash diets usually leave you even heavier than you were before. The best approach is to change your lifestyle: what you eat and what you avoid. Once you understand the concepts, you can move on to the specific steps.

I’ve never had a quick answer to the question, “Doctor, how can I lose weight?” Scientific evidence shows that 95% of people fail to lose weight and keep it off for more than a few months. Sure, most of us can shed a few pounds using the latest fad diet or miracle drug for a few weeks. Very few can maintain the weight loss. Our weight yo-yos up and down. Repeatedly losing and gaining weight is probably worse than not losing weight at all.

Recent scientific studies about weight loss show that no one diet and no single technique is clearly superior to any other. Clearly, whatever it is that drives us to overeat is more powerful than a simple drug or dietary trick. Weight-loss fads are valuable only to the people who peddle them. They make a bundle, provided they’re not concerned with telling the truth.

One way you know there’s no proven weight-loss system is there are so many of them. How many solutions are there to treat appendicitis? One: take out the appendix. How many schemes are there to get rich? A million, and most of them make money only for their promoters. Similarly, I don’t believe any of the prescription weight-loss drugs on the market are worthwhile for most people.

Certainly there are legitimate weight-loss approaches and programs. Among the best is Weight Watchers, which has been helping people to lose weight for decades. The amount that most people lose in Weight Watchers is modest, however, typically about ten lbs. Yet their diet is a lot healthier than many alternatives, and I recommend it to my patients.

So is losing weight hopeless? No, but just asking how can you lose weight may be the wrong question.

The new evidence

The new scientific evidence regarding weight loss yields some startling new perspectives on the topic. New evidence suggests the following:

  • Not all the fat on your body is equal. Fat on your hips, thighs, and chest probably does not threaten your health. But fat tissue within the abdominal cavity is highly metabolically active and can make you deathly ill.
  • Gaining weight is a lot easier than losing it. If you gain ten pounds and it stays put for a few weeks, it may reset your body’s “set point” to the higher value. Then when you try to lose weight, your body tries to gain it back.
  • Losing weight is not simply about eating less. That doesn’t work for most people because your appetite center gets even: you simply eat more later. It’s about eating smart, choosing what to eat and when to eat it. Included in this topic is timing your meals, eating the right foods, the role of fresh produce, caloric density, and the “Glycemic Index.”
  • Another key issue is managing craving. Closely related is “comfort food”: eating when you’re upset but not hungry.
  • Finally, it’s actually possible to burn fat. Certain foods can do this, but the most important fat burner is muscle.

Let’s address these one at a time.

Muscle is the enemy of fat

After age 35 we lose 1% of our body’s muscle — about half a pound — every year. When muscle mass drops, we need fewer calories, and it’s easier to gain weight. That’s why it often becomes more difficult not to put on pounds as we age.

If you exercise, you can maintain muscle mass. Ten pounds of muscle burns 140 calories of fat every night in your sleep. When you exercise aerobically, muscle metabolism turns on and burns extra calories for hours. Building muscle by lifting weights increases muscle metabolism for several days.

Avoid crash diets!

One of the most common patterns is becoming upset about your weight and going on a “lose all that ugly fat in three days!” diet. The problem with this approach is when you lose more than 1-2 pounds a week, most of what you lose is muscle, not fat.

Muscle is the only thing that will keep the weight off when you begin to eat again. If you lose muscle, you’ll regain the lost weight rapidly and then keep on gaining! There’s growing evidence that this yo-yo approach results in both metabolic damage to your body, and higher body weight than when you started.

The best approach is to bulk up — gain muscle — and lose metabolically active fat, as described below. That way the fat stays off.

Not all body fat is equal

The current emphasis on the epidemic of obesity stresses the incredible dangers of being overweight. Fat tissue increases insulin levels, raises blood pressure and blood sugar, and damages blood vessels. It commonly leads to diabetes, heart attacks, strokes, kidney failure, and other horrors. Losing fat clearly reduces the risk for all these illnesses and the death and disability they bring.

But it appears that the only fat that does this lies within the abdominal cavity, attached to the intestines and other deep structures. Most of our fat is superficial: it sits between skin and the underlying muscle. This “subcutaneous” fat has much less metabolic activity.

Indeed, a 2004 New England Journal of Medicine article shows that using liposuction to remove twenty pounds of fat from beneath the skin had no benefit on insulin or blood sugar levels! This is astonishing until you realize that liposuction can’t reach the fat within the abdominal cavity, which lies deep to the abdominal muscles. That’s the fat one has to worry about.

“Toxic mold”

Fat within the abdominal cavity can be called “interabdominal fat.” Doctors often refer to it as “visceral fat,” because it surrounds the “viscera,” or organs within the abdomen. I’ve found myself asking patients to imagine this fat as “toxic mold.” (Of course it’s not really mold or any kind of foreign substance, but this provides the right mental picture.) Excessive interabdominal fat literally poisons you, in the same way that people have been poisoned by toxic mold growing in their homes. And just as moisture within the walls of your house predisposes to mold, certain foods promote toxic interabdominal fat (more on this later).

How can you tell if you have too much deep abdominal fat? Measure your waistline just above the hip bones. Men’s waists should measure 30-36 inches (about 76-91 cm). If your waist exceeds 40 inches (101 cm), you have way too much interabdominal fat. For women, the desirable range is 25-31 inches (roughly 64-80 cm), and it’s time to worry when your waist exceeds 35 inches (89 cm).

Weight doesn’t matter as much as shape. One lesson of the importance of interabdominal fat is that your shape matters more than weight per se. If you work out, bulk up, and slim down as recommended here, you may not lose an ounce. But your clothes will fit differently, and you’ll be a lot healthier.

Are you overweight? How much?

You would think this was easy, but some (especially young women) obsess about being thin. The best way to determine your weight is a combination of waist size (see above) and body mass index (BMI).

Body mass index is roughly your weight divided by your height. Calculate your BMI at this NIH web page. Optimal BMI is 19 to 24.9. You’re overweight if the BMI is 25 to 29.9. Mild obesity is a BMI of 30-34, moderate obesity 35-39, and morbid obesity 40 or greater. BMI is falsely high if you’re very muscular and falsely low if you have little muscle mass, as is common over age 75.

If you’re morbidly obese (BMI over 40) or moderately obese with medical complications like diabetes or obstructive sleep apnea, you are a good candidate for bariatric (weight-loss) surgery. The proper procedure can dramatically lower your weight and with it your risk for heart disease, diabetes and its complications, and a host of other illnesses. Although some morbidly obese individuals can lose the 100 or more pounds necessary through diet and exercise, the majority cannot. The science is clear that despite the substantial risk of surgical complications, most people who qualify for surgery are a lot healthier if they undergo the procedure.

Avoid artificial or manufactured foods

Many commentators have wondered why we Americans are so much heavier than our counterparts in Europe or Asia. Part of the problem is we spend more time in our cars and walk much less. But much of the cause is “frankenfoods”: the industrial food products the average European or Asian would never eat. Read the labels of the foods you eat. How many ingredients are there? How many of the ingredients can you pronounce?

Eating right: Low fat or low carbs?

You’ve seen the controversy over whether we should eat a low fat diet (lots of carbohydrates) or eat more fats and cut carbohydrates, like the Atkins or South Beach diets. So which is better, low fat or low carbs? Until recently, I thought the answer was to cut both fat and carbohydrates and increase protein intake. Theoretically, high-protein diets cut food craving, curb appetite, and maintain muscle mass while you lose weight. But we can’t prove they work.

The problem with low-carb diets like the Atkins is it’s easy to load up on fat and high-calorie foods. Here’s a 2004 article from the excellent nutrition column in the Washington Post that discusses this problem further. Low-fat diets increase carbohydrate intake, which can predispose to the metabolic syndrome.High-protein diets often involve eating more fat.

A 2009 article from the New England Journal of Medicine shows that if you study people for more than a year, none of the diet types (low fat, low carbohydrate, high protein) were superior to the others. What counted were how many calories people ate. Not everyone agrees with this perspective: some believe a high-carbohydrate, low-fat diet is worse than the others, particularly if you have metabolic syndrome.

My bias is that different diets work for different people, and you may have to experiment to find out which one is best for you.

Eating right: Caloric density

Caloric density is the simple notion that some foods have a lot of calories per gram, and some very few. For example, to eat 100 calories of lettuce, you need a bucketful. One tablespoon of butter has the same 100 calories. You can get roughly the same number of calories in two oranges, 1-1/2 apples, or a third of a chicken breast.

High caloric density foods typically add weight faster than they satisfy your hunger. The worst offenders are junk foods high in fat and sugar. Fast foods are typically high in caloric density and offer low nutrition.

The Glycemic Index: Eating the right kind of carbohydrates

The term “carbohydrates” encompasses a multitude of foods, from simple sugars to starch and dietary fiber. I recommend against extreme restrictions on carbohydrates. Rather, you should avoid the ones that get you into trouble, particularly those that raise your blood sugar and insulin levels. How can you tell?

One system is called the “Glycemic Index.” You can learn more about it at, but that’s a fan site. The Wikipedia article is probably more balanced. In brief, glucose is the main sugar in your blood. It’s what becomes elevated if you are diabetic. Your body converts most sweet and starchy foods to glucose, but does so at different rates depending upon the food. Quickly digested foods cause a rapid elevation in glucose level and are more apt to lead to diabetes and fat accumulation than foods that are absorbed more slowly.

High Glycemic Index foods may promote interabdominal fat.

The Glycemic Index measures how fast your intestines absorb sweet and starchy foods. Each food has its own number, actually a percent that ranges from 0 to 100. By definition, glucose (simple sugar) has a Glycemic Index of 100: it’s absorbed into your body 100% as fast as glucose. A carbohydrate with a Glycemic Index of 50 is absorbed half as fast as glucose. The higher the number, the faster the absorption, and higher the resulting blood sugar and insulin elevations. Lower numbers are better. According to this system, you should shoot for carbohydrates with a Glycemic Index of 55 or less.

It turns out the Glycemic Index may be overrated. But a 2004 article suggests that in fact Glycemic Index is the best way to separate carbohydrates that make you fat (those with a high Glycemic Index) from those that promote less fat and greater lean body mass.

High Glycemic Index foods include candy, donuts, potatoes, bread, rolls, cookies, crackers, and most snack foods. White rice has a high Glycemic Index, but brown rice is lower. Ditto foods made from white vs. whole-wheat flour. Most fast foods have a high Glycemic Index. Most fruit, vegetables, beans, and other whole foods are lower. (Remember, lower is better.) Here’s a listing of the Glycemic Index of common foods.

Why not just take vitamins?

Many of my patients are convinced they need to take vitamin supplements for optimum health. When I ask why they believe this, they don’t really know. It just seems like common sense.

But what is a vitamin anyway? Vitamins were discovered in experiments from about 1880-1920 that explored what is the least you can feed a rat and not have it die. In other words, what is the minimum diet you can eat without becoming ill?

Certainly if you don’t get enough vitamin C you can develop scurvy. Deficiency of thiamine (vitamin B1) causes beriberi. Absence of vitamin A is one of the most common causes of blindness in people living in developing countries. But except in special circumstances (intestinal bypass, alcoholism, and certain other illnesses), vitamin deficiency is very rare in America if you eat a normal diet.

Why not play it safe and take extra vitamins just in case? It’s because vitamins are the answer to the wrong question.

We don’t care what the minimum diet is to keep a rat alive. We want to know what is the optimum diet for health. But vitamins are the minimum, and lots of minimum don’t produce the optimum. Studies of people taking lots of vitamins A, B complex, C, and E shows no health benefits from these supplements.

So what is the optimum diet? The science is clear: oodles of fresh produce. Certainly a tomato has lots of vitamins A and C. But it also has a hundred other nutrients (“phytonutrients”) that are not nearly as well understood but seem more important for optimum health.

Vitamin D may be different

In the last few years,  research has shown that vitamin D may the exception to the rule that vitamin deficiencies are rare in the United States. There are few natural food sources of vitamin D; mostly we get it from exposure to the sun. But these days Americans spend a lot more time indoors and are protected from the sun when outside. The Recommended Daily Allowance of vitamin D — 400 units a day — is probably too low; the correct figure is probably between 800-1200 units a day. As a result, many people have low blood levels of vitamin D. Serious Vitamin D deficiency can cause substantial health problems. Warning: massive overdoses of vitamin D can be extremely toxic or poisonous.

But reassessment of vitamin D suggests it may not be a cure-all. Most of the apparent benefit came from association studies: comparing the health of people in the community with their vitamin D levels. Those with higher levels were substantially healthier. But “correlation does not prove causation,” and past experience has shown that these types of studies reveal all sorts of false positive correlations that are actually just markers for people who take better care of themselves. To the best of my knowledge, no prospective randomized controlled trial has shown much benefit from vitamin D supplements. But the best trials are still underway. We won’t know for sure until at least 2020.

Eating right: Fresh produce

Very few Americans get the 4-5 helpings a day of fresh fruits and vegetables the US government has recommended for a healthy diet. It turns out even this number is too low.

People who eat 7-10 helpings a day of fresh fruit and vegetables are much healthier than those who eat less, whether one measures obesity, blood sugar, blood pressure, or risk of cancer or heart disease. And they find it easier to lose weight.

Ideally, you should vary the color of the fresh produce you eat. It turns out that fruits and vegetables come in six main color groups: green, yellow, orange, white, purple, and red. Each color provides different nutrients.

So to lose toxic fat, feel better, and look better, have three helpings of fresh produce with each meal. (But remember, potatoes and rice don’t count as fresh vegetables.) More than half your plate should be fresh produce. Indeed, the diet with the best evidence of promoting health is the Mediterranean diet.

Eating right: Avoid problem foods

Certain foods can add weight extremely quickly. Minimize the amount you consume of:

  • Any kind of soda. Regular soda contains high-fructose corn syrup, which is a major cause of the American epidemic of obesity. Even diet soda can cause weight gain. This sounds nuts — how can something with zero calories make you gain weight? No one knows for sure, but the science is clear. Diet soda is just as effective as regular at adding pounds.
  • Fast food. With the exception of particularly health-conscious restaurants like Koo Koo Roo, a particularly effective way to gain weight is to dine at any of the fast-food burger or pizza palaces.
  • Candy, pastries, sweets
  • It’s a crime, but there’s no weight loss benefit to artificially sweetened drinks or foods. It turns out these sweeteners trigger the same carbohydrate sensors in the gut as real sugar and cause an outpouring of insulin. Insulin makes you gain weight. It’s a growth hormone.
  • White starch (potatoes, white rice, white bread, white pasta). Most of these foods have a high glycemic index
  • For many people, red meat is a good way to gain weight. Moreover, recent studies show that people who eat the most red meat have a 30% higher mortality rate than those who eat the least. My recommendation is mostly to use small amounts of red meat as flavoring, like meat in spaghetti sauce, rather than devouring a slab of meat. Fish, chicken, and turkey are healthier. And if they’re prepared properly, they offer much lower fat and calories.

Managing craving: Trigger foods can sink even the best diet

Make a list of the 5 to 10 foods you crave the most when you’re upset or want a reward. These should include foods that make you feel better emotionally, or which you often eat more of than you intended, or that help calm you down when you’re upset. Typically these are the foods in your diet with the highest Glycemic Index and lowest nutritional value.

See if you can figure out which emotional needs these foods address. Can you meet these needs some other way? Which of these foods are you willing to eliminate from your diet? Which can you limit to a small portion just once in a while?

Burning fat: Building muscle mass

One of the most important tricks in changing your shape is increasing muscle mass. Each pound of muscle burns 14 calories a day, much of it in your sleep. Ten new pounds of muscle burns an extra 140 calories a day, enough to change the direction your scale is heading. Indeed, the reason it becomes harder to lose weight as we grow older is we lose muscle mass with age. You can regain most of this muscle through exercise, particularly weight lifting. I’m working on a new section on exercising properly.

Burning fat: exercise

Doing something that feels good and makes you pant and sweat for at least half an hour a day makes a real difference; six hours or more a week is better. The trick is to mix up different exercises that are comfortable and convenient. Mostly, this requires trial and error to find the right balance for you.

Foods that burn fat

Caffeine burns fat, as do hot peppers (cayenne and Tabasco sauce, for example). Black and especially green tea helps as well. These effects are small, but every little bit helps. One warning: too much caffeine is addicting and can elevate blood pressure. Caffeinated drinks like soda and “energy drinks” often add weight, even if they’re sugar-free. You’re better off with coffee or tea, which have a number of other nutrients that help lose weight and can lower the risk of heart disease.

So what’s the bottom line?

Go for the  Mediterranean diet. It’s harder to gain weight if you load up on fresh fruits and vegetables.

Recommended resources

The Mediterranean Diet Weight Loss Solution: The 28-Day Kickstart Plan for Lasting Weight Loss is by a noted dietician. Half of it is recipes and half an explanation of the Mediterranean diet and its advantages.