Kids love to ask questions. They want to figure out how the world works and make sense of it all. Unfortunately, this tendency sometimes fades with age...and it shouldn't! When research shows us that the vast majority of dieters gain the weight back, there are some big questions we should be asking: Why do we feel we need to diet in the first place? Why do so many people gain the weight back? And, when it obviously doesn’t work in the long run, why do we keep doing it?
Why do people diet altogether? Well, for starters, we live in a culture in which people feel compelled to achieve a certain body type. This is hugely profitable to several major industries. Just as individuals come in different heights and personality types, we come in all sorts of shapes and sizes, but by making all of us feel that we can – and should – strive to achieve one particular body type, the diet industry has capitalized on a huge market. And by hyper-focusing on the perceived dangers of obesity, they succeed in cashing in on an even greater population.
Health professionals love to say that their recommendations are “evidence-based.” What is the evidence when it comes to dieting? Linda Bacon, PhD, made it her mission to find the answers. She spent years researching the consequences of dieting. She obtained degrees in psychology, exercise science and physiology, with a special focus on nutrition and weight regulation. What Dr. Bacon discovered is truly fascinating, because it completely takes the wind out of diet culture’s sails – or more accurately, sales. She elaborates on the evidence in her book Health At Every Size, which I highly recommend. Her bottom line is that dieting does not make people thinner; it makes them fatter, unhealthier and unhappier. In fact, we’d all be a lot better off focusing on healthy behaviors rather than reaching a dream number on the scale (1).
Dieting is so harmful because when you diet, you’re messing with a good thing. Your body loves to be in a state called homeostasis. It’s that happy place where it feels comfortable and functions most effectively. When you’re too hot, your body will sweat to cool you off to bring you back to homeostasis; when you’re too cold, you’ll shiver to warm up and get back to your happy place. Your body works to maintain homeostasis in many physical properties, including weight. You have a built-in weight range at which your body functions best, which is referred to as your set point. When you try and tamper with it by dieting, your body will fight back to ensure homeostasis. Your preoccupation with food and your hunger drive will increase, while your metabolism decreases. Yes, initially you do lose weight when you consume fewer calories than you burn; dieting does work short-term, which is why people diet to begin with. But try and reach a weight that’s lower than what was intended for you, and your body will do its very best to get in your way.
The part of your brain that’s in charge of maintaining your set point is called the hypothalamus, and it senses your levels of hunger and fullness, as well as how much body fat you have at any given time. It responds to these signals in ways that help maintain your set point. If you are losing weight below your set point, it will make food more appealing to you and increase your cravings for higher-fat foods. It can also decrease your drive for physical activity. When you attempt to use willpower to overcome your hypothalamus’s efforts, it will take things to the next level by utilizing systems beyond your control, such as decreasing your body temperature to conserve energy and slowing your metabolism to use calories more efficiently. If you try and get below your set point, losing body fat will trigger your body to reclaim it.
Be aware that your set point isn’t one specific weight, but rather a range of several pounds. If you are at the higher end of your set point, your body won’t compensate if you try to lose weight, because it will still be within its comfort zone. It’s only when you aim to get below your normal range that your body will be resistant. Clues that you may be below your set point are often feeling cold, fatigued, irritable or depressed, waking up with an overwhelming urge to eat, and being constantly preoccupied with food.
So now we see why it’s hard to stay on a diet. But why do “successful” dieters end up gaining it all back plus more in the long run? This is because your body eventually catches on to your gig and sets a hormonal process in action that makes it very difficult to maintain a lower weight and may even increase your set point. With repeated loss of body fat, your body produces less of a hormone called leptin, which suppresses appetite, and more of an enzyme called lipoprotein lipase, which increases fat storage. Your weight-regulation system just doesn’t work well anymore. That’s why numerous studies indicate that weight regain occurs in dieters even when they maintain reduced-calorie diets (2,3).
But what about obesity? Isn’t it unhealthy? Are we all supposed to just do nothing about those extra pounds? Dr. Bacon addresses this in great detail, explaining that obesity is sometimes correlated with illness, but evidence does not support the notion that it is the cause of illness. Someone who is obese but has healthy eating habits and is physically active can be much better off than a thin person who doesn’t live a healthy lifestyle. Good nutrition and a healthy lifestyle are important for you regardless of your size. If you have gained weight above your set point due to unhealthy lifestyle habits, then adopting healthier behaviors can result in weight loss. But the cycle that results from dieting won’t make you healthier and, chances are, it won’t make you thinner. It’s become clear that trying to change your size may be far less healthy for you than accepting it and aiming to eat in the way that best supports your health instead. This is definitely a big challenge in our current food environment, so hang in there…we’ll talk about how to eat well next time!
FYI: If I don’t advocate dieting, how can I call myself a dietitian? The word diet actually means the kinds of food a person eats, and yes, helping out with that is indeed my job. But in our culture, diet has come to refer to a restrictive way of eating for the purpose of weight loss, and current research does not support this practice.
1. Bacon, Linda. Health at Every Size. Dallas: BenBella Books, Inc. 2008.
2. Howard, Barbara V., et al., “Low-Fat Dietary Pattern and Weight Change over 7 Years: The Women’s Health Initiative Dietary Modification Trial”, JAMA 295, no. 1 (2006): 39-49.
3. Gardner, Christopher D., et al., “Comparison of the Atkins, Zone, Ornish, and Learn Diets for Change in Weight and Related Risk Factors Among Overweight Premenopausal Women: The A to Z Weight Loss Study: A Randomized Trial,” JAMA 297, no 9 (2007): 969-77.