I once saw an eating plan that started with: "breakfast, one slice of wholemeal toast". (granted, it was a "womens magazine" not a "Health magazine") then wanted me to drink a glass of fruit juice and a piece of fruit.
My first thought was: my two-year-old eats more for breakfast than that. Second thought: if I replaced the sugar-laden, calorie-deprived juice with a boiled egg, I'd have half a chance of surviving until the meagre morning tea they specified. Third thought: the fruit was okay, but any moron could have thought that one up.
Choose your eating plan carefully. Remember that those bodybuilding products and workout gels and bars that elite athletes use are full of carbohydrates and calories. Which is great if you're an elite athlete. Not so great if it means two extra hours on the treadmill to work it off!