Response to "The Fat Trap"

It's well-known that when people don't get enough to eat, bad things happen to them, physically, emotionally, and cognitively. A lot of these changes (hunger, weakness, grumpiness, food obsessions, and worse) are related to the body needing something which it is not getting, and the attempt by the body to regain what was lost. This is true whether it's a normal-weight person who can't get enough to eat for whatever reason or an overweight person on a diet. When those people are able to eat normally again, they eat a lot, and after awhile, feel a lot better.

One of the main differences between reduced-carb diets and low-calorie diets which have a higher carb content is, interestingly, not so much in the difference in calories -- low-carbers tend to spontaneously lower the calories they are taking in. The difference is that people don't tend to have the negative reactions usually associated with weight loss. In fact, instead of feeling MORE obsessed with food, they often feel much LESS obsessed than before, with fewer cravings, more energy, etc. (after an adjustment period). The theory about this is that lower insulin makes body fat more accessible for use as energy. This essential hormonal change, it is thought, is what makes all the difference, and makes weight loss feel so much easier with carbohydrate restriction.

I think this is why the recent New York Times magazine article by Tara Parker-Pope, "The Fat Trap", has generated some negative reactions in the low-carb community. The article, except for two glaring omissions, is actually a good summary of what we know about body changes from weight loss. She starts with a study I wrote about in November about how changes in appetite hormones brought about by weight loss persist even after a year of weight maintenance, leaving people in a "biologically altered state". She writes about how these changes include a change that leaves dieters needing fewer calories for the exact same activities as their same-sized non-dieting counterparts, including changes in the muscle fibers. There are also changes in the brain's response to food. She also reviews some of the key evidence for a genetic basis for obesity.

Parker-Pope also interviews some people who have been successful keeping off weight long term, and what it takes for them to maintain their weight loss: basically lots of exercise (90-120 minutes per day is what the research says, and her interviewees agree) and obsessively recording, weighing, and measuring their food and themselves every single day for the rest of their lives. One woman admitted that she couldn't have done it while her children were at home. Retirement apparently gives you time for that new full-time job of weight-loss maintenance.

Gary Taubes (author of Why We Get Fat, Good Calories Bad Calories, and several New York Times magazine articles including the 2011 "Is Sugar Toxic?") has voiced a strong objection to issues left out of Parker-Pope's article. He has gone so far as to write (with Peter Attia, MD) an opinion piece that is framed as a petition to the New York Times that we call can sign. One objection is that in Parker-Pope's discussion of hormones there is one glaring omission: insulin, the master fat-regulating hormone, which is also the primary driver of carbohydrate metabolism. The other is that she leaves out any real evidence for what causes people to gain the weight in the first place, basically falling back on "we're eating more and exercising less". Well, obviously we're eating more, but why? Have people suddenly stopped heeding the hunger and satiety signals of their bodies? Or is it some hormonal imbalance such as "too much insulin" that is driving our appetites by making our fat less available as an energy source?

The saddest part of the article to me was that after elucidating all the evidence for the biological and genetic aspects of overweight and obesity, she still blames herself for her overweight state.

One issue I want to bring up, possibly more of a matter of emphasis than disagreement with Taubes and Attia. Certainly there is no doubt that carbohydrate restriction can promote weight loss, and perhaps more important, help normalize blood pressure, blood glucose, triglycerides, and cholesterol. However, it is not a blanket "cure" for obesity. (I frankly don't think there is such as thing.) For people who are very overweight, we cannot predict on an individual basis how much weight is likely to be lost, and low-carb eating will very likely will not bring them to their "dream weight". At that point, the mechanisms Parker-Pope elucidates DO most likely kick in. This is something I feel strongly about bringing out into the open. Many low-carbers are still blaming themselves for not losing enough weight, and that is, in my view, totally counterproductive. The main goal should be about health, not looks. I am quite overweight, but thanks to a low-carb diet I weigh less than I once did, and by all other measures I have my health back. That is my focus and I am truly grateful for it.

Photo: Tom Grill/Getty Images

Related Resources:

• Favorite Things About Low-Carb Eating
  
  
• Weight Loss Success Stories
  
  
• 20 Benefits of Low-Carb Eating

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