I can't believe I read the whole thing.
First, let me say that science journalist Gary Taubes's lengthy tome (460 pages of really fine print plus 113 pages of notes and bibliography!) is not a diet book. Good Calories, Bad Calories is a ginormous review of the scientific literature relating to obesity, heart disease, diabetes, and other "diseases of civilization (cancer and Alzheimer's, etc.)." It's also a bit of a diatribe against the public health establishment for recommending to the nation a low fat/low cholesterol/high fiber diet given the controversial, and since refuted, evidence that such a diet would prevent heart disease and obesity.
It's a fascinating, and difficult, read. Given the exhaustive nature of GCBC, I couldn't possibly summarize it for you. As a student of science, however, I do want to share with you what I learned about fat metabolism, obesity and hunger. Stay with me.
There is only one hormone in the body that is responsible for causing fat to be stored in fat (adipose) tissue: insulin. Guess which nutrient class is responsible for stimulating the release of insulin from the pancreas: carbohydrate, and ONLY carbohydrate.
When we eat a meal rich in carbohydrate, the pancreas releases insulin (the more carb., the more insulin). Insulin promotes the conversion of some of the carb. into fat, and triggers the incorporation of fat into our fatty tissues. Insulin also signals the fat cells to "hang on" to that fat for dear life, disrupting the release of fatty acids into the blood stream for fuel.
It goes like this (the simple version):
- We eat carbohydrates.
- Insulin is secreted from the pancreas.
- Glucose from our meal is either converted into fat and stored, or used by cells throughout the body for fuel.
- When blood glucose levels drop, cells throughout the body require a different source of fuel: free fatty acids released from fat cells.
- Unfortunately for our thighs, insulin inhibits the release of free fatty acids.
- No fuel is available to the cells, and hunger is stimulated.
- We eat more carbohydrates.
- It's a vicious cycle.
It's an eye-opening read.
Now I need to re-read and take notes!