I just finished reading Gary Taubes book “Why we get fat” after hearing him interviewed on Russ Roberts excellent econtalk podcast.

Gary wrote a book called “Good Calories, Bad Calories” a few years ago which is quite technical and includes a long history of how the state of nutrition got to where it currently is. “Why we get fat” is a well written distilation and update of his previous book.

The following surprising facts are from “Why we get fat”:

1. Lower testosterone or lower estrogen makes you fat because it has an inhibiting action on LDL which causes your fat cells to absorb more fat. That is why we get fat as we get older.
2. In an experiment, mice had their ovaries removed which removed their estrogen. They ate more and got fat. When their diets were limited they got fat anyway and became sedentary to compensate for the fact that they were storing away so many calories. This illustrates a recurring concept in the book: We are not fat because we eat too much. Instead, we eat too much because we are fat.
3. Beer is the perfect beer-belly creator because when you drink beer the alcohol is turned into citrate in your liver which aids in fat production. That’s fine, but the problem is that the carbohydrates in beer in the form of maltase cause an increase in insulin which put your fat cells into storage mode. So the new fat that the citrate produced is quickly and efficiently stored… where else but your beer belly.
4. A high protein, high fat diet raises your LDL (bad) cholesterol slightly, but massively raises your HDL (good) cholesterol which has a strong net positive effect on your overall cholesterol.
5. A high protein, high fat diet causes your LDL (bad) cholesterol to appear in larger clumps which are less likely to stick to your artery walls.
6. High insulin levels caused by carbohydrate intake cause atherosclerosis (hardening of arteries).
7. Up until 1960 the popular advice from nutrition experts was to stick to a low carb diet. Gary includes a huge amount of data and historical quotes to support this. After 1960 we somehow got screwed up and started thinking that carbs should for the base of the food pyramid.
8. Fat does not make you fat. Carbs make you fat because they boost insulin levels which put your fat cells into absorption mode and prevent your fat cells from breaking down triglycerides into fatty acides and glycerol and releasing them to be used as energy.
9. The reason you instantly lose 3 to 6 pounds when starting a low carb diet is because your high insulin state has been signaling your kidneys to absorb sodium which causes them to retain water. When you lower your insulin levels for the first time your kidneys release that water and you lose (in my case) 4 pounds in about 36 hours.
10. When you eat only protein and fat, your body goes into a state of ketosis after a while which means you are using fat as energy. You can buy ketostix at your local pharmacy and perform a urine test to see if your body is in a state of ketosis and at what level. The ketostix I have include a blood glucose test on a separate color panel which is also useful data.
11. Gary attacks the idea that you can only lose weight by decreasing calories in or increasing calories spent through exercise with the following illustration: If you accidentally over-ate 25 calories per day for 20 years you would gain 50 pounds in weight. Most of us eat outside of that narrow threshold, but our bodies manage to self regulate somehow.
12. Most diets fail because we decrease calories consumed which simply causes us to decrease our energy expenditure and stay the same weight.

It’s a great book and completely changed my view on nutrition and physiology as it relates to diet.