Why Diets To Lose Weight Fail

Almost everyone who has tried to lose weight has tasted the bitter pill of failure. That feeling you get when, despite all your desires to be healthier, to fit into sassier clothes or to shimmy through life (and into aeroplane seats) with greater ease and comfort, you just can't stick with your diet and exercise plans for long enough to get there.

Weight loss picture from Shutterstock

People failing to lose weight frequently blame themselves, as does almost everyone around them. In fact, even a sizeable proportion of health professionals consider obesity to be an individual failing. But this attitude displays complete ignorance of human physiology and how it impacts weight loss.

Fighting famines, not winning weight wars

In actual fact, most diets fail because the body activates a series of powerful physiological mechanisms — many originating from changes in the hypothalamus, which lies at the base of the brain — that help to protect us from losing too much weight too quickly.

These mechanisms, which I call the famine reaction, have been pivotal to our survival as a species because they prevent ongoing weight loss and promote weight regain. In pre-agricultural times, which forms the majority of human history, food supply was much more dependent on seasons and intermittent. Conserving energy ensured survival through the lean season.

But while the famine reaction undoubtedly helped the species survive recurring famines and hardships, it presents an enormous challenge in modern societies where the abundance of food (especially energy-dense food) means many people are now overweight or obese.

The famine reaction is a whole-of-body response to not getting enough food with three main symptoms.

  • Hunger — when you start a weight-loss program, you might not feel very hungry at all. But once you lose a certain amount of weight, you can eat your whole day's diet ration and still feel hungry … and it's only 10.30 in the morning.

That's the famine reaction pushing you to eat more and help protect you from losing any more fat.

  • Lethargy — keeping active can be a challenge at the best of times, but when you've lost weight and your famine reaction has been activated, you can feel like you're dragging your whole body in mud just to get through the day.

You're being slowed down so you don't waste precious energy and lose any more fat.

  • Feeling cold and shivery, even in the middle of summer — this is your famine reaction reducing your metabolic rate. The result is that weight loss can come to a complete standstill (or plateau), even if you're still sticking rigorously to your diet and exercise plan.

These effects are incredibly powerful, and help explain why most people hit a plateau and gain back some or all of their lost weight shockingly quickly.

Health-care professionals, the weight-loss industry and members of the public alike assume the energy-conserving effects of the famine reaction are only felt by lean people after extensive or rapid weight-loss (because they need to be protected from wasting away).

But this adaptation has been shown to happen even in overweight and obese people after loss of as little as 6% to 12% of body weight. And even in cases when weight loss has resulted from moderate energy restriction, with or without physical activity.

Fighting the famine reaction

If you listen to standard advice from the majority of weight-loss programs, you'll think the famine reaction and its secret weapon, hunger, will just go away with judicious use of willpower.

All you have to do in the meanwhile is ignore how hungry you're feeling, or try to quash your hunger by filling up with non-starchy vegetables, which are part of the "free list" in most diets because their low calorie and carbohydrate count means you can eat as many of them as you like.

But research shows the brain changes that cause the famine reaction don't just dissipate if you hang in for long enough and exercise more. So what can you do to avoid regaining the weight you've lost?

One way is to work with your physiology, rather than against it. This means eating more at certain times, notably when hunger raises its troublesome head.

Research shows eating more and undergoing a period of weight maintenance (rather than continuing efforts to lose weight) can deactivate aspects of the famine reaction. In particular, it can block the reduction in metabolic rate that creates those tiresome weight-loss plateaus.

This intermittent approach to weight loss — eating less overall but sometimes eating more — may improve the efficiency of weight loss. It may also reduce the drive to eat large amounts of food when you've lost some weight, by taming the hunger pangs of the famine reaction. My colleagues and I are currently investigating this strategy in a clinical trial.

We still need to determine the optimum timing of intermittent energy restriction for different people. But if you're on a diet and start to experience mounting, nagging hunger (a sign of the famine reaction at play), eat the types and amounts of (mostly healthy) foods that make you feel genuinely satisfied.

This may ultimately help weight loss more than the conventional advice to just keep going. It may even be a suitable weight management strategy for people who struggle with binge eating.

If you live in the Sydney metropolitan area and would like to find out about participating in our weight-loss trials, please click here.

Amanda Salis is NHMRC Senior Research Fellow in the Boden Insitute of Obesity, Nutrition, Exercise & Eating Disorders at the University of Sydney. She receives funding from the National Health & Medical Research Council (NHMRC) of Australia, in the form of research project grants and a Senior Research Fellowship. She is the author of The Don't Go Hungry Diet (Bantam, Australia and New Zealand, 2007) and Don't Go Hungry for Life (Bantam, Australia and New Zealand, 2011) and owns shares in a company (Zuman International Pty Ltd) that sells these books.

The ConversationThis article was originally published on The Conversation. Read the original article.


Comments

    I am relieved to notice that there's a shift happening in the way we think about weight loss and the individual. While there is always some high-ish level of personal responsibility, there are definitely other factors that need to be considered, and I can't wait for some real discussions on how to effect change.

    I appreciate your article. But the reality is that one can not lose weight by exercising. This accepts the antiquated idea that we are steam engines and all we have to do is burn the off off or burn up the calories like a steam engine burns coal.

    To lose weight and keep it off we must understand the cause of weight gain in the first place. The cause of weight gain is mineral deficiency. It is often said that we are what we eat. The fact is we are what we can absorb. When we ruin our digestive tract by eating the wrong foods such as wheat, barley, rye and oats we are unable to absorb nutrition. You may notice that these foods all contain GLUTEN.

    80% of the public is gluten intolerant. This means that when we eat gluten in bread, pasta, cereals, ice cream, gravies, sauces etc. we end up corrupting our our digestive tracts and destroying the absorption mechanism.

    Further, the foods that we eat are devoid of the minerals that humans require to be healthy. There are 90+ vitamins and minerals that are required. There is no way that a person can eat all 90+ nutrients in today's diet.

    The idea that exercise is the key to losing weight is a myth. That is like saying people are fat because they are lazy and lack exercise. In fact, exercising may put added stress on the body causing it to become more deficient and telling the body to store carbohydrates as fat.

      You Sir/Madam are full of the waste product of eating Gluten. Care to provide any peer reviewed research to back up your quackery/pseudoscience?

    I think you use the term diet loosely here. I'm sorry, but I just completed an intensive 12 week program. I changed my eating habits, worked out 5 times a week (including 40 minutes of cardio daily) and lost 22kg, and put on close to 10kg in muscle. Being on a diet does not mean you eat less, in fact, I eat 5-7 times a day and I simply monitor what I eat. I do not count calories, and often treat myself, but there really are some things you should just avoid. I've maintained the diet, I enjoy the food and it's easy to prepare but cut down the intensity in which I train.

    Exercise may not be the key to losing weight, changing eating habits can greatly reduce your size, but exercise is key to building strength, increasing dexterity, feeling great, and in my opinion, looking great.

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