May years ago I had a discussion with a personal trainer colleague of mine. I was young and hungry, and he was definitely more established than I at the time. He had some really nice training programs that yielded some decent results. He was also good looking, which helps when you are a trainer, and he was exceptionally personable. The thing was he didn’t know squat when it came to nutrition. His basic philosophy was “calories in , calories out.” That is the basic methodology of many trainers and nutrition centers like Weight Watchers etc. It can work, to a point, but back to my story. He was saying that basically his clients can eat whatever they want, so long as the they burned more calories than they took in. He did not care what the macronutrient ratios were, just the caloric total. Ok…. So I gave him a challenge. Pick any 2 clients, put them on a 2000 calorie diet. One client can only eat Frosted Flakes. The other client could only eat chicken breasts and broccoli (not nutritionally balanced, but you get the point). Put them on the same training program and see who loses the most fat after 4 weeks. Not surprisingly he did not take the challenge. He insisted that it was all math, and that so long as the calories coming in were less than the calories being expended, the client would lose weight. I knew I would never change his mind, so I left it at that.