Alisa Anokhina explains in her health keynote that diets fail because people are thinking in the wrong way. She goes on to talk about the psychology of dieting and how ideas like eat less and exercise more are in fact fallacies that result in failure to lose weight. She talks about the need to look deeper at how humans live and think about food.
Anokhina's health keynotes promotes not relying on self control and suppression, but rather work around and make adjustments. If a person wants pizza, there's no need to deny oneself their craving, instead make a healthy pizza -- make a healthy pizza with healthy ingredients and savor it. Another way is to get exercise by doing activities for enjoyment rather than weight loss. The important thing is to form healthy habits around one's preferences rather than conform oneself to a fad diet that won't work.