In the last few weeks I have read "Good Calories, Bad Calories" by Gary Taubes. Taubes has degrees in physics, aerospace engineering, and journalism, and has been a writer for
Science Magazine for years, one of the top scientific journals. His book is apparently the #1 best seller in occupational medicine at amazon.
http://www.amazon.com/Good-Calories-Bad-Controversial-Science/dp/1400033462
I bought this ~450 page text to learn more about nutrition. To be honest, I was concerned I would read 450 pages and learn nothing, as nutritional science tends to be extremely qualitative. This wasn't the case, every chapter in the book was bursting at the seams with research results from multiple studies, that were explained in detail. The work of hundreds of researchers spanning hundreds of studies over 150 years was thoroughly and exhaustively explored, leading to several conclusions, some of which were surprising.
The following arguments are convincingly made:
1)
Saturated fats and fats in general have nothing or nearly nothing to do with heart disease. The ostensible link originates from 1950s/1960s arguments of the "7-countries study" and other completely spurious pseudo-scientific arguments that should have never been published. Beyond that point, additional arguments were made because researchers invested in the 7-countries study didn't want to lose face.
The 7-countries study from Ancel Key found a correlation between fat consumption in 7 countries and heart disease, which is where most of the popular link originates. However, the correlation does not hold within the countries, and as pointed out by Taubes, the 7 countries were selected in order to deliver the correlation. Including more countries leads to the absence of a correlation. For example, in the 1990s it was considered a "paradox" that the French ate a high-fat diet and had low rates of heart disease.
https://en.wikipedia.org/wiki/Seven_Countries_Study
The other factor noted is that the links in association studies are hard to deal, as many samples in western countries involve people who eat diets both high in animal fats and high in sugar. For example, anybody who goes to McDonalds as a high-fat, high-sugar diet. These people then get heart disease, which is used as evidence that fats cause heart disease.
I'll note that it is now common knowledge that dietary fats have nothing to do with heart disease. However, it was still a provocative argument when Taubes made it in 2007.
2)
Cholesterol is a misunderstood variable, it isn't intrinsically bad for you to acquire additional cholesterol molecules in the blood. Much of the concerns with cholesterol originate from the fact that it was among the first variables that doctors could reliably measure, so doctors correlated everything with cholesterol. However, first we believed high cholesterol was bad, then we believed high LDL cholesterol was bad, and that HDL cholesterol is in fact good. Taubes details how a lot of researchers were frustrated with the evidence that high HDL cholesterol is good for you, as it created confusion. Beyond that point, Taubes details that even LDL cholesterol is a composite variable, and some parts of it appear to be actually quite good for you.
Those who are my age (32) may remember that when we were children "low cholesterol" foods were said to be a good idea. We don't see low cholesterol advertised on foods anymore, as it's since been demonstrated that blood and dietary cholesterol have nothing to do with one another, and regardless, blood cholesterol is not flat out bad for you.
The evolution can be seen here:
3)
Metabolic Syndrome, which is when a person has at least 3 of 5 of abdominal obesity, diabetes, elevated blood pressure, high-serum triglycerides, and low HDL cholesterol,
is a "disease of civilization", likely caused by high carbohydrate consumption and in particular high consumption of sugars and simple starches.
An impressive argument in the book, that Taubes does consistently, is detailing how tribes across the world, from the Zulu to the Eskimos, did not suffer from metabolic syndrome when they were eating low-carb diets, even as consumption greatly exceeded 2,000 calories a day. This is found all over the world, regardless of whether or not saturated fats come from animals (Eskimos) or from coconuts (a tribe near New Zealand) and even as they constitute >~30% of dietary calories. However, as simple flour and white sugar were introduced to these communities, and as they migrated to cities and began consuming more westernized diets, obesity emerged. This is not too surprising, but what I did not know is that cancer and alzheimers emerged as well.
An interesting finding is that among these tribes,all over the world, it was documented that blood pressure decreased with age, rather than increased as is common in the west.
4)
Obesity is an issue of fat metabolism, rather than energy balance.
This struck me by surprise, as recently as a few months ago I would have told you "calories in versus calories out" but Taubes succeeds in comprehensively dismantling this position, which shocks me. What Taubes argues is that this is an association, rather than a causal relation, and the causality happens to go in the other direction.
If we see an 18 year-old who is 6'5 and another who is 5'5, we don't say that the 6'5 teenager is taller because he consumed more calories. We believe he's taller because he has different genes and different metabolism and hormones. He did in fact likely consume more calories, but that's because he was driven to do so by his biology, rather than the extra calories making him taller.
It's similarly observed in rat experiments. Fat metabolism matters. There are types of rats that are driven to obesity ... given the same amounf of calories, they will be far fatter. In partial agreement with the popular view that obesity is a psychological disorder caused by too much gluttony, one can make these rats have normal weight by starving them. However, they then still have high body fat percentage, as their muscles are gone and all of their organs are starved. Starvation is thus not ideal in this case.
Evidence is also found from hibernating animals. It's extremely hard to prevent them from gaining weight in the periods where they're supposed to gain weight.
5)
A calorie isn't a calorie.
An assumption of the argument that obesity is a psychological disorder is that resting metabolism is fixed. It's not fixed. Taubes argues in the book that resting metabolism can crash in response to a high-carb, low-calorie diet, for example by showing that weight loss slows down long-term in those undergoing starvation diets, far earlier than one runs out of body fat.
It's since been confirmed that a high-carb diet slows down metabolism at fixed total calorie consumption. A recent study found a metabolic offset of ~400 calories in a day between a 60% fat diet and a 20% fat diet:
http://jama.jamanetwork.com/article.aspx?articleid=1199154#COMMENT
6)
Insulin is a dominant variable in fat metabolism. When insulin levels are elevated, the body seeks to grow fat cells, as well as not draw energy from fat cells. When insulin levels are low, the body draws energy from fat cells. A diet which lowers mean insulin levels in the blood will thus be more efficient in the long-term at increasing fat metabolism.
7)
High-fat diets increase satiety. The higher the fat content of the diet, the more satisfied people are, even at low calories. In contrast, in low-fat diets, subjects have been observed being hungry even when consuming upwards of 10,000 calories a day, in experiments. I think we all know this from experience ... jelly beans and chocolate chip cookies can be eaten
ad infinitum, whereas the same is not true of steak and mushrooms. The latter is eventually satisfying and one stops eating.
8)
Historically, low starch, low sugar diets were the standard advice for weight loss. Dozens of supporting studies are discussed. It was only in the 1970s that low-fat diets became the standard advice. This was true all over the world. It was particularly in the USA that researchers advocated high-carb diets. Many of these researchers received grants from Coca Cola.
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All in all, I'm now convinced that I should be consuming fewer carbs, and particularly fewer simple carbs, and more fats. I've found that it's extremely difficult to do so. Our entire society is based on carbohydrate consumption. We get served carbs on airplanes, at airports, and at parties, as I've found recently. You can go to most restaurants and not find a single low-carb meal. Steak usually comes with fries, you don't always have a sauteed spinach option.
Another problem I've found is that North Americans don't know what yogurt is. I now live in Australia now, and most yogurts here, nearly all yogurts, are extremely high in sugar, something offensive to Europeans as well. I went to Whole Foods yesterday and I could not find a single yogurt that had more grams of fat than grams of carbohydrates. It's absurd.
Within North America, "Greek" yogurt means 0% fat. In the rest of the world it means the exact opposite, it means very high fat. It's really bizarre. Anyway, most of you won't understand these two paragraphs since you all believe that yogurt should have 0 grams of fat and 30 grams of sugars.
There are other scams to be found in north american supermarkets, like skim milk.
