Misinformation about overweight and overeating is rampant. Very few individuals have accurate information about the true causes and proper treatments of overweight. This misinformation means that overweight individuals usually make their condition worse when they diet. Now, let’s review the most common weight loss myths so that you can guard against them.
Perhaps the most pervasive and destructive myth about weight loss is that dietary fat causes excess body fat. Because of this myth Americans are eating less fat than ever before in history. Yet obesity in American is at an all-time high: 70% of Americans are seriously overweight. Since the 1970s, dietary fat intake has gone down, and overweight has gone up. Clearly, excess dietary fat is not the primary cause of overweight.
There’s an intuitive logic in the idea that dietary fat causes excess body fat: to be less fat, eat less fat. In reality, however, the most important thing about dietary fat isn’t how much of it we eat, but what happens to it after we eat it. Dietary fat can be burned for energy, stored in fat cells, or eliminated from the body (in urine as ketone, especially).
What happens to dietary fat after we eat it depends on certain chemical signals in our blood stream. The dietary fat does what these signals tell it to do: burn for energy, go to storage as body fat, or go into the urine for elimination. We’ll describe these signals later, and how to control them to lose body fat—which doesn’t require reducing fat in your diet.
Sadly, the American medical establishment clings stubbornly to the notion that excess dietary fat is the most serious cause of overweight. The “Food Pyramid” still reflects this idea, and encourages severe restriction of fat intake. Ironically, the Food Pyramid has been one of the main causes of the increase in obesity in the US over the past 30 years.
Fortunately, since 2000 several medical studies (one presented at the annual meeting of the American Heart Association) have conducted head-to-head comparisons of low-fat diets and low-carbohydrate diets. The low-carb diet has come out on top in all studies: more fat loss, less muscle loss, and better cholesterol and triglycerides levels. Therefore, recently more physicians are accepting the idea of the superiority of the low-carb diet. The American Diabetic Association has also recommended the low-carb diet for diabetics.
The myth that excess calories are the cause of overweight is almost as destructive as the myth of excess dietary fat. This calorie myth is appealing because it seems to make common sense. Here’s how the logic goes: Body fat is used for “energy”; calories are a unit of food energy; eating excess food energy (calories) must result in excess stored energy (body fat).
This myth treats our body like the simple gasoline tank in your car. If you put extra gas in your car, any “extra” that you don’t burn is kept in storage (in the gas tank). The problem with this idea is that our body is much more complex than a simple storage tank.
In reality, excess “energy” (calories) can indeed be stored in the form of body fat, but it can also be “dumped” as waste products in urine. Biochemical signals determine whether calories are stored or dumped. It’s not the calories per se that are the problem in overweight—it’s having your body’s signals in the “store-fat” mode rather than the “dump-fat” mode that is the problem.
Fortunately, we are learning more about the bodily signals that determine whether you are in the “store fat” or the “dump fat” modes. By shifting your body into the “dump fat” mode via a low-carb diet, you don’t have to restrict calories to lose weight.
Another destructive myth about weight loss is the belief that to lose weight you have to be hungry. Here again there is an intuitive—but erroneous—logic to this: If overweight is caused by overeating, then “under-eating” should correct it; and since we’re hungry when we under-eat, then being hungry must lead to weight loss.
Actually, just the opposite is true: to lose weight you must never be hungry. Here’s why: you can be hungry for a while, but eventually you will eat, and almost certainly overeat more than ever because you’ve gotten so hungry. Hunger leads to rebound overeating, and to overeating the wrong kinds of foods (more about that later). Also, studies show that if you’re hungry your brain will reflexively slow your metabolism to protect against starvation. This slower metabolism means you burn fewer calories, which makes it harder to lose weight.
So part of the key to losing weight is never being hungry—to avoid slower metabolism and rebound overeating. Luckily, as long as you follow a low-carb diet, you can eat as much as you want, never be hungry, and still lose all your excess weight.
The most guilt-inducing myth about overweight is that all of your eating is totally under your rational control, and that willpower is the key factor leading to weight loss success. On its face, this myth seems perfectly reasonable. After all, no one shoves food down our throats. We must consciously and voluntarily put food into our mouths and swallow it. Even before that, we must consciously choose what kind of food to eat. We can start and stop eating anytime we want, right? What could be more under our voluntary control?
Yet, even individuals with lots of “willpower” are unable to stop overeating. I have many patients who are very successful in life, and have accomplished many things that required strong willpower. Many of my weight-loss patients have persevered through years of toil to attain a goal important to them. Some of them have suffered through physical privations with little complaint. For many of them the goal of losing their excess weight is as important as any goal they’ve ever achieved. Yet permanent weight loss is the one goal they can’t achieve. Why is losing weight so different from the many other goals they’ve achieved through their willpower and intelligence?
Losing excess body fat is different from other goals because it’s due to overeating carbohydrates, which is a type of addictive-compulsive behavior. Addictive overeating has much in common with cocaine abuse, alcoholism, and compulsive gambling. These are behaviors that, for many people, are (ultimately) irresistible. They are due to chemical imbalances in the brain circuits that control our urges and appetites. The power of these urges overrides our “rational” intentions, which are (biochemically) much weaker. I’ll discuss this in detail later.
Trying to resist addictive-compulsive urges produces intense mental and physical discomfort. The combination of the urge to eat and the physical discomfort eventually will drive you to over eat carbohydrates almost 100% of the time. It’s like having a severe itch. You can resist scratching for a while, but eventually you will scratch. Willpower, as usually defined, has little to do with it. I’ll say more about the source of these irresistible carb cravings in a later chapter.
Rather than trying to resist the addictive-compulsive urge to overeat, the solution is to reduce that urge coming from the brain circuits. Medications are an important part of this solution. I’ll give much more detail about this later.
This brings up another destructive myth: that “diet pills” are addictive or dangerous. The medical term for diet pills is anorectic medications. They reduce food cravings.
The original anorectic medications were amphetamines. These were first used in the 1930s. Some amphetamines can be quite dangerous, and can produce a strong chemical and psychological dependency. They can do permanent brain damage and can produce serious clinical depression.
Since the 1970s we’ve had much safer anorectic medications that are not addictive and that have few side effects. Now we have combinations of modern medications that are very effective in both reducing the urge to overeat and in reducing excess weight.
Unfortunately, most individuals—including most doctors—still view all anorectic medications as though they were the amphetamines from the 1930s. Most states still have laws severely limiting the prescribing of all anorectic medications, even the safe ones.
The phen-fen problems in the mid-1990s further hurt the public and professional image of weight loss medications. Phen-fen was a combination of two medications: phentermine and fenfluramine (Redux, Pondimin). Fenfluramine increases the brain’s level of a chemical called serotonin. Raising serotonin helps to reduce food cravings, and I’ll talk more about this in a later chapter. However, fenfluramine raises serotonin too much, and not just in the brain. These high levels of serotonin can damage the fragile tissues in heart valves and lungs.
As a result, fenfluramine was removed from the market in the middle 1990s. It’s important to realize that the only weight loss medication implicated as causing these problems is fenfluramine. Yet many laypersons—and physicians—saw the phen-fen problem as a condemnation of the entire category of weight loss medications.
There is no evidence that modern anorectic medications are significant health risks. On the other hand, there is a wealth of evidence that being overweight is a very severe health risk.
No doctor would consider withholding medications to treat high blood pressure, even though some medications for high blood pressure have had problems with serious side effects. Yet most doctors do withhold, or too severely limit, medications to reduce serious overweight. This is one of the major “blind spots” in modern medicine. To lose weight successfully and long-term, you must find a physician who has the proper understanding of how to use modern weight-loss medications. I’ll discuss how you can find such a physician in a later chapter.
A final myth about weight loss is that aerobic exercise is best. On the surface, again this seems to make common sense. When we run, jog, use a stair-step machine, swim, etc., we burn more calories and burning more calories should mean that we’re burning off excess fat because body fat is “stored calories,” right? Well, that’s only part of the truth.
We burn calories every day in three ways:
- Maintaining our basic metabolism (just keeping our body alive)
- Digesting the food we eat
- Physical activity
Maintaining our basic metabolism burns about 70% of our calories each day. Digesting the food we eat burns about 15% of our calories each day. Our physical activity burns about another 15% of our calories each day.
The number of calories we burn for our basic metabolism is called our Resting Metabolic Rate (RMR). Again, our RMR burns about 70% of our calories each day.
Our RMR is determined mainly by the amount of muscle we have. The more muscle, the higher our RMR, and the more calories we burn each day. The most effective way to burn more calories each day is to increase the amount of muscle in your body. This is more effective than simply increasing activity. By increasing activity via aerobic exercise, you’re increasing just a small fraction (15%) of your daily calories burned. By increasing your RMR, on the other hand, you’re increasing a much larger portion (70%) of your calories burned each day.
Weight lifting type exercise (“strength training”) is the best way to increase your RMR. Aerobic exercise increases muscle endurance, but doesn’t increase the size of muscle fibers much; so aerobic exercise doesn’t increase your RMR very much. For that, you need strength training.
But even more importantly than increasing RMR, strength training also makes your body more sensitive to insulin, allowing you to secrete less insulin each day. This is an important part of resetting your body’s biochemical signals to get rid of body fat by excreting it in the urine. I’ll go into more detail about this later.
For strength training exercise you can use free weights (such as dumbbells or even plastic milk jugs filled with water or sand), weight machines, or the inexpensive elastic band type exercisers. Exercising twice weekly for about 30 minutes each time is sufficient. Strength training is the fastest and most effective way to exercise. I’ll give more details about strength training in the chapter on that subject.
- Overweight is not due to excess dietary fat or calories
- Overweight is due to your body’s being in the biochemical “store-fat” mode
- Hunger is not necessary to lose weight; in fact it is important not to be hungry
- Lack of willpower is not the reason people can’t stick to a weight-loss diet; irresistible addictive-compulsive urges to overeat are the problem
- Modern anorectic medications (“diet pills”) are not significantly dangerous; they are non-addictive and are very effective when properly prescribed
- The most important type of exercise for controlling weight is strength training, not aerobics
Now that we’ve put aside the most common misinformation about overweight, let’s start discussing the truth about overweight. Let’s start by discussing the food type that is virtually always the cause of overweight.