"Working out is only one piece of the puzzle in weight loss — the most important piece is food and diet," explained Williford. Everyone wants to just exercise to lose weight and not make any adjustments to their food intake, but this is an error in the mechanics of weight loss. Food and diet are the drivers for weight loss, and exercise is meant to support the calorie deficit that you need to lose weight. She said, "regardless of the number of days of exercise, the person must be in a calorie deficit to lose weight."