Dietary strategies focused solely on reducing intake of bad foods or calorie restriction, like Weight Watchers, are ineffective for long-term weight loss because they don't address the root cause.

“most of the dietary strategies that we employ are not focused on improving the quality of the food, nor are they necessarily focused on reversing the pattern of a westernized diet. They're more focused on simply reducing the westernized diet and eating less of a bunch of bad foods. I'm thinking of things like Weight Watchers or other calorie restricted patterns. That's exactly the same problem that got you into this mess and got you obese. You're just eating less of it.”