Health at Every Size (HAES) is a lifestyle that encourages healthy eating and enjoyable physical activity as a way to feel better and live longer. Unlike other programs, it does not believe weight loss through dieting is the way to become healthy.

Scientific evidence supports this idea. In a 2006 study by researchers at the U.S. Department of Agriculture, 78 obese women were placed into either the Health at Every Size program or a traditional weight-loss program. Women in the weight-loss program were instructed to eat less, count calories, and exercise more.

The Health at Every Size group was encouraged to eat when they were hungry and to appreciate the feeling of fullness, to make healthy food choices, and to find a style of physical activity that was most enjoyable for them. They were not given a list of "forbidden foods," nor were they told to exercise to lose weight. They were also given techniques to build their self-esteem and to increase the confidence they had in their bodies.

After two years, both groups weighed approximately the same. The women in the weight-loss group lost some weight after six months, but regained it after two years. The women in the Health at Every Size group had healthier blood pressure, lower cholesterol, and were more physically active than the dieting group.

The study's results came as no surprise to Linda Bacon, researcher and author of Health at Every Size: The Surprising Truth About Your Weight. Bacon holds a Ph.D. in physiology with a focus on nutrition and weight regulation.

"Health at Every Size is about taking care of your body without worrying about whether you're ‘too’ big or small," she says. "People might think they can tell who's fit and who's not by looking at them, but in fact, it's trickier than that. Lots of people are fat and fit—many avid dancers, runners, lifters, and sports team members are big to start with and stay that way. They tend to be far healthier than thin people who don't move around much or eat a nutritious mix of foods.

“Saying everybody needs to be the same weight is like saying all people should be the same height."

Diets Don’t Work

Your body's weight is determined by genetics. Like height or skin color, weight and body type vary from person to person. A person's ideal weight range is called their set-point weight.

Your set-point weight is controlled by a part of the brain called the hypothalamus. The hypothalamus regulates the body's feeling of hunger and satiety—the full feeling you get after you've eaten a meal. One of the jobs of the hypothalamus is to keep you as close to your set-point weight as possible.

When you go on a diet and lose weight, your hypothalamus interprets the sudden weight loss as a problem somewhere in the body. It will do whatever it can to get you back to your set-point weight. The hypothalamus will release hormones to increase your appetite. It will slow down your metabolism, so you don't lose weight quickly. It will even make you feel more lethargic, or sluggish, and less likely to exercise.

Dieting can backfire by resetting your set-point weight at a higher level, to protect your body against the sudden changes of future diets.

"No one who diets is fit,” Bacon says, “because dieting hurts your metabolism, and your metabolism determines how your body uses energy.

“But diets not only don't work—they're making us fat. Scientific studies show that if your weight 'yo-yos,' if it goes up and down a lot, that leads to long-term weight gain, especially when you're young. Teens' and preteens' metabolisms are trying to figure out what their adult pattern will be. Diets interfere with that. People with stable weights, even high ones, often enjoy better health than dieters and ex-dieters."

Fat Isn’t the Problem

In 2004, the Journal of the American Medical Association reported that 400,000 obese and overweight Americans die every year. That's the information it got from the Centers for Disease Control and Prevention (CDC).

However, the CDC later learned that the methods by which it got those numbers were faulty. When it re-did the report with better methods and new data, just 26,000 overweight or obese people a year died—fewer than the number who died due to guns, alcohol, or car accidents. The deaths were typically from people who had a body mass index (BMI)—a measure of body fat based on height and weight—greater than 35. Most overweight people are in the lower range, from 30 to 35.

In fact, life expectancy in the United States has risen—along with the obesity rate—from 70.8 years in 1970 to 78.2 in 2009. In its revised study, the CDC found that overweight people actually live longer, with 86,000 fewer deaths in the overweight category than in the normal weight category. And underweight people died more often than either overweight or obese people, suggesting that the thinnest people in the U.S. may be at a greater health risk.

In Health at Every Size, Bacon writes, "Many well-meaning scientists and medical practitioners are misled about the ill effects of being heavy. There is clearly a correlation between obesity and certain diseases and conditions, like diabetes or hypertension, but that doesn't mean being fat causes these conditions. It may be that whatever causes the diabetes also causes people to gain weight.

“To help explain this, one example I like deals with bald men and heart disease: Influential studies show that men with hair loss are more likely to have heart attacks. Does that mean going bald causes heart attacks? And can keeping your hair (or getting hair transplants) protect against cardiovascular disease? Well, of course not! After research and analysis, the baldness-heart risk association still isn't totally clear, but it appears that testosterone—which can cause both baldness and heart problems—is a likely culprit.

“In other words, fat isn’t the problem. When we see diseases that are more common in fatter people, it’s more about what they’re doing, than they’re fat. So the key is to make healthy changes in what you do and stop worrying so much about weight."

Health at Every Size

Health at Every Size focuses on health, not weight, as an indicator of your overall well-being. But if weight isn't a measurement of our overall health, how do we know we're healthy?

Bacon says, "Weight distracts us, and this focus results in poor medical care for everyone. 'Normal weight' people—who may have poor health habits and disease—don’t get good diagnoses or support for changing habits, which may catch up with them. People in the overweight and obese categories get stigmatized, encouraged in restrictive eating—even if they may actually have great health habits to begin with. Perhaps this could be a better focus for medical care—interviewing people about whether they have social support and manage stress well, whether they are regularly active, if they eat well.

"What's good for thin kids, fat kids and everyone in between, it turns out, is moving their bodies and a healthy mix of foods that taste good and nourish our bodies. Finding activity you enjoy might mean sports or workouts, but it could also be walking, jumping rope with friends, or dancing.

“With eating, Health at Every Size calls for intuitive eating. This means learning to listen to your body so you can recognize when you're hungry and when you're full, and what foods satisfy you. You don’t get as many nutrients from food when you don’t enjoy it, so do take care to choose foods you love. Sugar and candy can taste great, but they don’t give you other nutrients your body needs, and you’ll find that you can get grumpy, tired, and don’t do so well in school if that’s all you eat. And if you skip the fruit and veggies, you’ll probably find yourself struggling in the bathroom too long, so you don’t want to avoid those. So mix it up and get a range of nutrients in you to keep your body function best and to keep you most alert and in a good mood. Experiment with food to see which ones make you feel best."

Bacon also recommends trying a range of foods to find ones that you enjoy. "What I find even more interesting is that research supports that people actually absorb more nutrients from meals that appeal to them than from meals they find less appetizing.

“In one interesting study, researchers fed a traditional Thai meal of rice and vegetables spiked with chili paste, fish sauce, and coconut cream to two groups of women, one Swedish and one Thai. The Thai women, who presumably liked the meal better than the Swedish women, absorbed 50 percent more iron from the same food than the Swedish women. And when the meal was blended together and turned to an unfamiliar and unpalatable paste, the Thai women’s absorption of iron from the meal decreased by 70 percent! So choking down the plate of steamed broccoli (if you hate steamed broccoli) is not likely to do you as much good as you think. Enjoying your food is an important nutritional practice."

The Health at Every Size plan doesn't put restrictions on the foods a person eats. Rather, it places more trust in the person to select foods that are right for them, and to stop eating when they feel full. Bacon says, "Have you ever noticed that, when you hear you can't have something—like ice cream, say, or chips—you want it all the more? Health at Every Size gets rid of 'in' and 'out' lists for food. If we trust our bodies and learn to listen to our appetites, they'll lead us to a healthy mix of foods and signal when we've had enough. When you can eat what you want and need, cravings and the munchies aren't such a problem, and you're no longer in danger of eating out of control."

Bacon writes, "What no one needs, at any size, is to feel bad about how they look or what they weigh. People who live by Health at Every Size ideas tend to feel better about themselves, and that can lead to better health, too, with less stress and disordered eating."