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The Ultimate Glycemic Load Diet and Cookbook
By Robert Thompson, DANA CARPENDER
The McGraw-Hill Companies, Inc.Copyright © 2012Robert Thompson and Dana Carpender
All rights reserved.
Understanding Why You Gained Weight
It's enough to drive you crazy. You're constantly battling your weight while others seem to stay thin effortlessly. They don't exercise, they eat anything they want, but they don't get fat. The perplexing thing about the obesity epidemic—and this has been true of other scourges throughout history—is that some people are more vulnerable than others. They suffer from the harmful effects of our modern lifestyle, while others seem to be immune. Overeating and lack of exercise are not the whole story.
But for years, people thought that being overweight was a matter of choice. Just as some folks played golf or did crossword puzzles for enjoyment, others got their kicks from eating. Doctors knew of certain hormonal disturbances that could make people gain weight, but they thought these were unusual. Most overweight people just chose to be the way they were.
Of course, who in their right mind would choose to be fat? If it came to a decision between being overweight or getting hit by a truck, some people would probably opt for the truck. Almost everyone would agree: obesity is unattractive, cumbersome, and unhealthy.
Being overweight, then, suggested you were either weak-willed or had some kind of psychological problem. However, when psychologists got around to studying overweight people systematically, they came up empty-handed. It turns out that overweight people are psychologically no different from thin folks. They have some bad habits, but no more than anybody else. They get a little depressed, but who wouldn't be? One thing is certain: they aren't weak-willed. Obese people often show remarkable self-discipline in other aspects of their lives. After all, 65 percent of Americans are overweight. Do all of these people have some kind of character defect? Of course not.
It's Not a Matter of Willpower
Do you remember when you were a kid and you tried to see how long you could hold your breath? It was easy at first, but after a minute or so, you developed a different mind-set. Lack of oxygen triggered chemical reflexes that told you in no uncertain terms you needed to breathe. Certainly, the need for oxygen is more urgent than the need for food, but the principle is the same. If you reduce your caloric intake, changes in your body chemistry stimulate powerful hunger-driving reflexes that overrule lesser concerns like how good you look. When those instincts say "eat," unless you have unusual willpower, you eat. You can postpone it for a while—and you have some control over the kinds of foods you eat—but if you try to defy the urge, you usually come away the loser.
The reason self-deprivation rarely works for losing weight is that it defies deeply rooted survival instincts. Consider this: Your body burns about 1.2 million calories a year. If your weight depended on your consciously regulating the amount you eat, misjudging by 2 percent (that's about two bites of a potato a day) would add or take off forty-two pounds in ten years. Who can fine-tune their eating that much? Your body can't afford to rely on your whims. It has its own mechanisms for balancing calorie intake with energy output.
Just as a lack of willpower didn't make you gain weight, simply willing yourself to eat less is unlikely to result in lasting weight loss. You might think you can dial down your calorie consumption at will, and maybe you can for a while. But let's face it: if you're like most people, you'll eventually return to your old ways.
A Matter of Hormones
In recent years, scientists who study body chemistry have discovered several hormones that regulate body weight. Here are a few examples:
Your thyroid gland makes a hormone called thyroxin, which helps regulate how fast your body burns calories.
Your stomach secretes ghrelin to stimulate your appetite when your stomach is empty.
Your intestines produce peptide YY to curb your appetite when your intestine has enough food to work on.
Your fat cells secrete leptin to reduce your appetite when your fat stores have been replenished.
Those are only some of the hormones known to control weight, and scientists are still discovering new ones. The point is this: powerful chemical reflexes regulate the balance between the calories you take in and the rate you burn them off. Body weight is not simply a matter of choice.
The hormone systems that regulate body weight evolved over millions of years during times when hunger was a constant threat. Although these mechanisms helped keep fat accumulation in check, their main purpose was to prevent starvation. Of course, our diet and activity patterns have changed a lot since the Stone Age, but our body chemistries work the same. When our weight-regulating systems sense we're not getting enough to eat, hunger-stimulating hormones arouse powerful cravings, and energy-regulating hormones reduce the rate at which our bodies burn calories. The desire to eat dominates our thoughts, and our bodies do everything they can to replenish fat.
So the reason you're overweight is not that you lack willpower. It's because something upset the systems that match your caloric intake with your energy expenditure. Certainly, choices were involved. You influenced the form those calories took—whether they were carbohydrates, fats, or protein—but your body's weight-regulating mechanisms determined how much food you needed to quell your hunger. You can't ignore those instincts. Mustering up the discipline to starve yourself is not the answer. You need an approach that doesn't rely on willpower.
But if you have such little control over how much you eat, how can you lose weight? It's easier than you think, but you just can't do it by a frontal assault on deeply rooted survival instincts.
There are dozens of ways to lose weight. You can cut fats, cut carbs, count calories, fast, go on an exercise kick, or have your stomach stapled. But if a particular problem—say a hormonal imbalance, a lifestyle quirk, or a certain kind of food—caused you to gain weight, does it make sense to starve yourself without trying to correct the conditions that caused the problem in the first place? If you don't fix what's wrong, whatever caused you to gain weight is bound to come back and haunt you.
Unlocking the Mystery of Obesity
In recent years, billions of dollars have been spent on researching human metabolism, and indeed, medical science has made major breakthroughs in solving the mystery of obesity. Although these advances have been obscured by the usual controversy, junk science, and diet hype that surround the issue of weight loss, old ways of thinking are being turned upside down. Scientists now have a clearer idea of why people's weight-regulating mechanisms fall out of kilter and what can be done to put them back in balance. Here is the picture that is emerging.
If you're like most overweight people, three conditions converged to cause you to accumulate excess fat:
1. You inherited a common genetic quirk that affects a type of muscle fiber in your body called a slow-twitch fiber, making these muscles resistant to the effects of insulin, a hormone needed to metabolize the sugar glucose.
2. Lack of regular activation of your slow-twitch fibers causes them to spend too much time in a metabolically dormant state in which they don't respond normally to insulin, a condition called insulin resistance.
3. The insensitivity of your muscles to insulin makes you vulnerable to the harm
Excerpted from The Ultimate Glycemic Load Diet and Cookbook by Robert Thompson, DANA CARPENDER. Copyright © 2012 by Robert Thompson and Dana Carpender. Excerpted by permission of The McGraw-Hill Companies, Inc..
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