Overeating Doesn't Make You Fat, Getting Fat Makes You Overeat

Yes, that's right: New science tells us that overeating doesn't make us fat. But getting fat makes you overeat. Take a moment to digest that.

A new comprehensive study stakes the bold claim that overeating doesn't cause obesity; the process of getting fat actually causes overeating. The research sheds new light on what causes weight gain and proposes a new model for weight management to solve the obesity crisis.

The study, published in The American Journal of Clinical Nutrition and authored by a team of 17 internationally recognized experts, argues that the century-old 'energy balance' model for weight loss is outdated and has proven ineffective. They have a point: Even as we diet and try to reduce our calorie intake in all manner of diets, rates of obesity are rising, affecting more than 40 percent of American adults. Instead, the authors say, we need to be paying more attention to the types of food we eat and how they affect our hormones and metabolism, leading to excess fat, which in turn drives more weight gain.

The latest science once again points to high glycemic load foods as driving up insulin, which then signals to the cells that energy is available. When the cells shout back "we're full" it prompts fat-storing, to get the excess glucose parked and out of trouble. These high glycemic index foods are wreaking havoc on our metabolism. Glycemic load (GL) measures the amount of available carbohydrates in a food and how much they raise blood sugar. GL is similar to the glycemic index (GI) but is thought to be a more accurate measure. High GL foods include refined carbohydrates such as white bread, pasta, and rice, pastries, cakes, cookies, and sodas.

While many people already know to avoid these foods to lose weight, it's not the number of calories they contain that are the problem, but rather what the food does in our bodies.

Refined carbs drive fat storage which causes overeating

When we eat refined or processed carbohydrates, insulin goes into overdrive, sending the body signals to store calories as fat, which leaves fewer calories available for muscles and other tissues to use as energy. The brain perceives that the body needs more energy (since our energy is now locked away in deep storage) and increases our feelings of hunger. That two-fold blow causes our metabolism to slow down to conserve energy. The result is that as we burn fewer calories, gain more fat, and become more hungry – so we eat more and gain weight. This is how eating the wrong foods (not too many calories per se) causes us to gain weight and it's why the scientists who conducted the study propose that getting fat causes overeating. Not the other way around.

The problem with counting calories

The approach that doctors and health experts advise for weight loss is the 'energy balance model' which sees all calories as equal and expects someone to lose weight if they have a calorie deficit and exercise more. For example, the USDA advises that to lose a pound of weight a week you need to cut 500 calories a day, or cut 1,000 calories a day to lose two pounds a week. (A pound is equal to about 3,500 calories so you need to eat that many less to lose a single pound, this argument goes.)

While this approach may work for some people, others can't maintain low-calorie diets and will end up putting the lost weight back on over time, causing them to feel like a failure. Additionally, as already explained, when the body senses fewer calories are coming in, it can hold onto weight and signals the brain to eat more high fat or sugar-laden foods to get the calories it believes it needs to survive. It's a vicious cycle that can cause someone to feel depressed and eat more comfort food.

Furthermore, counting calories does not consider the effects of specific foods on thyroid hormones and on our stress hormone cortisol — since prior research tells us foods can upset the balance of these (by disrupting blood sugar) and drive up even more weight gain.

Rather than simply counting calories, the study authors propose 'the carbohydrate-insulin model' is a more effective approach to lose weight and keep it off for good. This approach means eating whole foods that have a lower GL to promote weight loss, less hunger, and more energy.

What to eat and avoid for effective weight loss

The authors advise a strategy of avoiding high GL foods, eating healthy high-fat plant foods, and allowing for moderate intake of carbohydrates from whole grains, whole fruits, legumes, and starchy vegetables. The following lists food to eat and avoid that fall within these categories.

Foods to avoid:

sodas and sugary drinks, including fruit juice with added sugars
cakes, pastries, cookies, desserts, and sweet treats
white bread, pasta, and rice
takeaway meals and ready-meals with added sugars and trans fats
potatoes and fries
chips and processed snacks
dried fruit
packaged breakfast cereals and cereal bars
sweetened dairy products such as yogurt

Foods to eat:

non-starchy vegetables such as green beans, leafy greens, salad greens, peppers, zucchini, cauliflower, broccoli, mushrooms, eggplant, Brussels sprouts, and onions
healthy fats such as olive oil, avocados, olives, nuts, and seeds
whole grains such as brown rice, quinoa, barley, spelt, and buckwheat —eat these in moderation
legumes such as chickpeas, kidney beans, navy beans, pinto beans, lentils, fava beans, and green peas —eat these in moderation

Additionally, the authors advise that someone with insulin resistance may need to have a stricter reduction of carbohydrates, but a person should speak to their doctor or dietitian about this.

The Bottom Line: Eating a low GL diet and paying attention to the number of whole-grain carbs such as rice and beans that you consume may be more effective than reducing calories.

Calorie deficits work for some but if you're one of those people that hits a weight loss plateau or puts it all back on, this approach can kick start your weight loss and help you to maintain it.

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