The cause of obesity is insulin resistance brought on by a high carb diet, recommended since 1980 by the USDA. The spike in obesity and diabetes began in 1980. Insulin is by far the most dominant chemical with regards to fat storage. We were told to eat 6-11 servings of grains per day, along with unlimited amounts of fruits (carbs) and veggies (many have carbs)--and we complied. Add to that sugar everywhere, fast food, eating 5-6 meals a day (ie snack foods) and it's a giant recipe for disaster. Studies on keto diets are showing high fat, low carb works, while the calorie model does not. Although the Keto diet studies keep coming, it's been established that the Carbohydrate-Insulin Model is superior to the calories in-calories out models. Ancel Keys was wrong: high fat, especially saturated fat, does not cause, or even correlate, with heart disease. Unfortunately, the US gov't is having a hard time turning this huge ship around and making recommendations based on science: eat plenty of fat, moderate protein, and low carbs.