If you listen to Gary Taubes (author of Why We Get Fat, and Good Calories, Bad Calories), you would believe that the reason we are fat is because we eat too much carbohydrate, and that the way to solve the problem is to stop eating carbohydrates.
I’m not sure that the facts exist to support Taubes’ thesis. One hole, is that we in North America are fatter than virtually everyone else in the world (32% of men and 35% of women in the US are obese), but we eat less bread than they do. In fact North Americans ate an average of 60 lbs of bread per capita in 2000, which is less than half of what the skinnier Spaniards (15% of men and 21% of women are obese), Danes (no data found), and Germans (20% of men and 21% of women are obese) ate.1,2
So we eat fewer carbohydrates than Europeans do, we are fatter, but it is carbohydrates that are making us fat?
Mr. Taubes takes his theory a step further and suggests that it is the low-fat diet fad that began in the last 30 years that has caused this alleged increase in carbohydrate consumption. But if you look at the data, Americans have actually increased their fat intake more than they have increased their carbohydrate intake. Wait, what? Mr. Taubes, how can this be? You told us we are getting fatter because we are eating too many carbohydrates and not enough fat. But as our girth increases, so does our fat intake.
A report from the Food and Agriculature Organization (FAO) of the United Nations shows that over the past 10 years, American’s have3:
- increased their fat intake by 7%;
- increased their overall calories by 2%; and
- their protein intake has remained the same.
The report does not identify carbohydrate intake, but we can infer from the total calorie, fat and protein intake that the portion of calories from carbohydrates has dropped by 1.5%. This was calculated using the 9/4/4 calories/gram factors for fat, carbohydrate and protein.
I kept looking because I didn’t want to jump to conclusions too quickly, and came across the Statistics Canada publication, Food Statistics 20054. The following table shows changes over time in energy consumption, macronutrients, and types of fat. The percentage column is calculated from the 1976 and 2005 values.
|Per capita:||1976||2005||Percent Change|
|Mono-unsaturated fatty acids (g)||40||49||23%|
|Poly-unsaturated fatty acids (g)||13||20||56%|
|Saturated fatty acids (g)||28||27||-2%|
I will point that Statistics Canada notes that the values in the table should be used with caution because “The data have been adjusted for retail, household, cooking and plate loss”. So we should not jump the gun and drive major policy decisions based on these values. But since the trend is similar to that shown by the FAO, maybe it deserves consideration.
Both the FAO and Statistics Canada show trends of:
- Increase in calories consumed.
- Proportional increase in carbohydrate intake.
- Disproportionately large increase in fat intake.
- Disproportionately small increase in protein intake.
In other words, we are eating more food; and relatively speaking, we are eating more fat, less protein, and about the same amount of carbohydrate as we were 35 years ago. And we are a lot fatter than we were 35 years ago.
That just doesn’t add up to “it’s the carbohydrates”.
How is it that Mr. Taubes’ thesis misses the mark? Because he bases it on outliers. He uses a series of exceptional examples as proof for his approach. But designing a system or validating a thesis with exceptions is not sound science. There exist exceptional circumstances to every working system and every truth. Exceptions are interesting, and their impact should be assessed; but it is incorrect to make them the basis of proof. Not only does Mr. taubes’ thesis miss the mark by defining a nutritional system based on outliers, but he encourages us to repeat the “fat is evil” mistake of the 80s with his “carbohydrates are evil” movement.
That’s right, I think “it’s the fat” is also a flawed approach to nutrition. Just as flawed as “it’s the carbohydrates”. But unlike Mr. Taubes, I don’t believe there is any conspiracy behind it. In fact, I think it was actually a good plan gone wrong. In fact I’m going to share my theory about how low-fat went wrong, but please note that this is merely an idea:
I believe that the non-fat movement may have started as a sound nutritional approach, with the idea being that if you are going to eat junk food, it is best to limit the amount that you eat. Low-fat junk food alternatives can mean that someone who would have eaten 1 cup of chocolate ice cream (500 calories) can instead eat 1 cup of chocolate frozen yogurt (250 calories). This means the overall junk food portion of their energy intake will be 12.5% instead of 25% (based on 2000 calories a day). I think most would agree that that is a good tradeoff (not eating the junk food would be better, of course). Unfortunately this concept was later applied beyond junk food to all foods, where healthy fats were replaced with empty carbohydrates. That is no longer a good trade. I certainly agree that reducing the empty carbohydrates in our diet and increasing the healthy fats and proteins should be part of a healthy nutrition plan.
If the problem is not the carbohydrates, then what is it?
A much simpler answer to the obesity question is that we eat more because we are served more.
National Geographic published a great article on this topic in 2004 called “Why Are We So Fat?”. Serving sizes everywhere from movie theatres to McDonalds have grown exponentially. Everyone over 30 can attest to the truth in that statement.
In addition to serving size, the change in the type of fat we consume is very interesting. We are eating 56% more polyunsatured fat, 23% more monounsaturated fat, and 2% less saturated fat than we used to.
Gary Taubes does talks about the reduction in saturated fat in our diet as a problem. Interestingly, Dr. Andrew Weil proposed this as a problem in his book, Eating Well For Optimum Health. He suggests that our increase in mono and poly unsaturated fats relative to unsaturated fats is causing an imbalance in omega-6 to omega-3 fatty acids, which is throwing our system out of balance and leading to our increase in girth. I remember reading this book about 10 years ago (his big white beard on the cover is hard to forget) and thinking that made a lot of sense. Seeing these numbers in the table above is making me think about that again. If you haven’t read that book, you should consider picking it up. It is a good read, although Dr. Weil also points to a series of exceptions to support his theses.
The idea of fat type is also addressed by Dr. John Berardi. Ensuring a relative balance of all of the 3 main fat types is #5 of the Precision Nutrition “10 Habits”.
So what are we to do? What is the one true diet? Is it low fat? Is it low carbohydrate? Is it low calorie? Paleo? Zone? Frequent feedings? Intermittent fasting? Yes, is the answer. And by that, I mean, the One True Diet is the one that you will follow. The truth is that they all work if you follow them. And they all fail if you don’t.
Elsbeth Vaino is a personal trainer in Ottawa, Canada.
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1. . Maple Leaf foods annual report for 2003, http://library.corporate-ir.net/library/18/189/189491/items/146682/InvestorPresentationApril2003.pdf
2. 2008 data from the International Association for the Study of Obesity, http://www.iaso.org/iotf/obesity/