The obesity epidemic is the number one public health problem. Gary Taubes, a writer for Science magazine, investigated the science of obesity and discovered that the evidence does not support the current paradigm. The reigning belief is that obesity is too much food and too little exercise. Wrong. And, the basic knowledge was there before WWII and into the post war era, but was lost in the war. The low-fat, heart healthy view became dominant even though repeated clinical trials failed to support it. 

Obesity is neither gluttony nor sloth nor a psychiatric problem (the most recent additional paradigm). It is a disorder of fat metabolism driven by excess carbohydrates that drive insulin up. Insulin then drives fat storage in fat cells and blocks release of fat from fat cells for fuel. We do not get fat because we overeat. We overeat because we are getting fat. The high insulin partitions fatty acids into the cells, keeping them from being used as energy, and we stay hungry for fuel. Vicious cycle. All this is supported by mountains of evidence.