“I am the one who got myself fat, who did all the eating. So I had to take full responsibility for it.” – Kirstie Alley
Unless you’ve been camping out in the Gobi Desert for the past decade, you probably know that Americans are the fattest group of people on the planet. And we’re getting even fatter. The agencies with the responsibility to carefully track these numbers are the Centers for Disease Control and Prevention’s National Center for Health Statistics.
According to their statistics, 66 percent of all adults in the U.S. over age 20 are overweight. Of these, 32 percent are obese. Compare that to 30 years ago when only 47 percent of adults were overweight, and only 15 percent of those were obese. We are clearly in the midst of an obesity epidemic.
So, how did we get ourselves into this mess … and is there any way out?
2 Glaring Omissions
Perhaps the most blatant bit of failed advice for healthy eating is that offered by the USDA Food Pyramid, now known as “My Pyramid.” The original Food Pyramid, which was offered up to a trusting American public in 1992, told us we should eat less than 30 percent of our total calories as fat. Because no recommendations were made for protein (then about 15 percent of total calories), that left carbohydrates to make up 55 percent or more of what the USDA considered an optimal diet.
Since the original Food Pyramid guidelines were implemented, the numbers of overweight and obese Americans have risen from 55.9 percent of the population to the current 66.2 percent. And all while they dutifully followed the government’s high-carbohydrate, low-protein dietary recommendations. In fact, carbohydrate intake has actually increased, particularly the consumption of high-glycemic-index carbohydrates in the form of refined grains and sugars.
In both the original Food Pyramid and the current “My Pyramid,” absolutely zero mention is made of the glycemic index of foods. This gives the message that dietary fat caused us to be fat, and that replacing fat with carbohydrate could prevent obesity and promote good health. Unfortunately, this message has now been shown in hundreds of peer review scientific journal articles to be simplistic, incomplete, and even erroneous.
The Glycemic Index
As you know from reading Dr. Sears’ past articles in ETR, the glycemic index, originally developed in 1981, is a relative comparison of the blood sugar (glucose) raising potential of various foods. In 1997, the concept of glycemic load was introduced to assess a food’s blood glucose raising potential based upon both the quality and quantity of dietary carbohydrate in a serving.
Refined grain and sugar products nearly always maintain much higher glycemic loads than unprocessed fruits and vegetables.
For people interested in losing weight, the importance of the glycemic index and load is that the blood sugar response is closely related to the insulin response. An exception to this general rule is pasteurized, homogenized dairy products, which exhibit low glycemic indices and loads, but paradoxically elicit high insulin responses similar to white bread. So when you eat a bowl of cereal for breakfast, not only does the cereal perilously raise your blood sugar and insulin levels, but the milk you put on the cereal raises your blood insulin level even further.
Hundreds of scientific studies completed over the past decade show that high-glycemic-index carbohydrates cause hormonal and blood chemistry changes that increase the appetite and promote weight gain. That’s why you need to stick to low-glycemic foods if you want to lose weight.
You might think the nutritionists who designed the revamped “My Pyramid” would be all over these exciting new developments. Not a chance. Highly glycemic foods are ubiquitous in the Western diet, and now comprise 47.7 percent of the per capita energy intake in the U.S. Is it any wonder that two-thirds of us are now overweight or obese?
Protein – Another Missing Link for Weight Loss
Governmental regulatory and advisory institutions are known to move slowly. But when it comes to dietary recommendations to prevent weight gain and obesity, they have not moved at all since 1992. Except for a superficial stab at including exercise as part of the new “My Pyramid,” major dietary recommendations remained virtually unchanged between 1992 and 2005.
The current “My Pyramid” recommendations for the three macronutrients are as follows:
- fat: 20-35 percent of total energy intake
- protein: 18 percent of energy intake
- carbohydrate: 55 percent of energy intake
The actual intake of these macronutrients is:
- fat: 32.8 percent of total energy intake
- protein: 15.4 percent of energy intake
- carbohydrate: 51.8 percent of energy intake
As was the case with the glycemic index, there is absolutely no mention of the benefit of higher-protein diets in promoting weight loss in the current “My Pyramid,” despite hundreds of well-controlled scientific experiments verifying this phenomenon. The decades-old perception is that to reduce body fat, you must reduce dietary fat, replacing the fat calories with carbohydrate calories. The problem with this approach is that people using it experience constant hunger, and any weight loss is typically modest and hardly ever stays off for the long haul.
But contrary to this old belief system, you can reduce your body fat by limiting carbohydrate and increasing your consumption of protein.
Believe it or not, the first well-controlled scientific study that traded out dietary fat, not with carbohydrate but with protein, did not take place until 1999. Scientists at the University of Copenhagen put 65 overweight and obese men and women on one of two diets:
- a reduced-calorie, high-protein, low-carbohydrate diet, or
- a reduced-calorie, high-carbohydrate, low-protein diet
After six months on the low-carb, high-protein diet, subjects lost almost 20 pounds, whereas subjects on the high-carb, low-protein diet lost only 11 pounds. And these results weren’t a fluke. This type of experiment has been repeated and confirmed dozens of times in the past seven years.
A growing consensus in the scientific community is that high-protein diets (where protein makes up 25 to 35 percent of total energy) are more effective at promoting weight loss than calorie-reduced low-carbohydrate diets because of their superiority in reducing hunger. Protein has a two to three times greater satiety value than either fat or carbohydrate, so people spontaneously eat less when they consume more protein. Of carbohydrates, fat, and protein, protein causes the greatest release of a gut hormone (PYY) that reduces hunger while simultaneously improving central nervous system sensitivity to leptin, another hormone that controls appetite and body weight regulation.
The scientific jury is in. High-protein diets are the way to go. So if you want to effectively lose weight, keep it off, and hold your hunger at bay, IGNORE the USDA’s “My Pyramid” and stick to high-protein and low-glycemic foods. Your body will thank you for it.[Ed. Note: During the past two decades, Dr. Loren Cordain has researched the effects of diet on human health, specifically examining links between modern diets and disease. He is the author of The Dietary Cure for Acne, and publisher of the The Paleo Diet Newsletter.]