Sunday, September 25, 2011

Book Review: Why We Get Fat: and what to do about it

'Why we get fat?' or more specifically 'Why I get fat?' is the question I ask every times I look at myself in the mirror before shower. 

The answer has come timely when I shopped the library two weeks ago and found Why we get fat: and what to do about it by Gary Taubes in the new books collection. He has written another book called Good Calories, Bad Calories which seems to be quite successful (New York Times best seller), so I am expecting this new book to bring forth some good advices. 

Indeed, Taubes has cleared some of our (my) misconception in weight loss. A lot of us might think that weight gain is due to overeating - eating more than the body requires. The logic behind is: overeating -->  excess calories --> gaining fat. To lose weight, therefore, we need to be on diet and to exercise more. 

However this is misleading (as most common senses are). First, our body is such a complex biological mechanism that this simple logic oversimplifies everything. Even if we expend more energy than we consume, we might still gain weight. 

The book has offered several interesting examples. In one experiment, the scientists removed the ovary of a rat. Then it eats voraciously until becoming obese. The scientist, suspecting the rat has overeaten, restricted the amount of food for the rat. Surprising, it still grows obese but has been more inactive (to save energy for making fat). 

In another example, Taubes found that most overweight and obese cases happen in poor neighborhood and undeveloped countries. If  the poor people don't have much money even to buy food, why do they grow fat and obese? Well, in Hong Kong, I have noticed that many bar - bending/construction workers are quite fat, provided they work so industrially.

So overeating and lack of exercise don't seem responsible for weight - gain. Conversely on diet and exercise won't work. Then what causes fat? 

Second, overeating what? All food? Fatty food? Sweet things? Carbohydrates? Some might indiscriminately cut all food. Some for fatty meat and others less rice. In any cases, we fail to realize how our bodies deal with those foods. 

The short answer to all these questions is insulin. Insulin activates fat - making cell to store fats in muscle and stops the body from using fat as fuel. What causes the secretion of insulin? Carbohydrates. Rices and noodle raise the glucose level that alerts the body to secrete more insulin to deal with them. 

Taubes proposes us to eat meat, all meats, including even all the fats with it, and zero carbohydrates. 

All very well, and  Taubes seems to have offered us a ultimate solution. But I do have some skepticism in his reasoning.

He said that our bodies have adapted to eating meats, rather than carbohydrates, because the pre - historic human can only hunt whatever they eat, i.e. meats and fats. But human at the time die at their 40s. Further I suspect those people simply had no choices and so they all die early. 

Indeed, in What to eat now in Time Magazine (September 12 issue), Dr.Oz has a point in saying 'I would rather follow a diet that sees me lucid and active enough to play with my grandchildren than one under which I die young but look great'. 

Taubes kept referring evidence and physicians in the 1940s/1950s and criticized the whole medical health community in the 1960s and 1970s has stuck with the old paradigm and bad science. While I don't out rule this possibility, I find it hard that the best minds in the medical community (of the 20th century) can't spot the fat - causing insulin (especially when Taubes sounds as it is a simple truth). 

Anyway, the bottom line is that we can all reduce the amount of carbohydrates in diet, but definitely not meat (if not to increase it). 

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