I hear a lot in the fitness industry about the importance of clean eating. Indeed, most fitness professionals quote that physical appearance is 80% due to nutrition and 20% due to your workouts. I don’t know where those numbers come from, but those percentages are unknowable.
If we are to assign a relative importance to each, it’s presumptuous to think that the specific foods we eat are more important to our health, fitness, and cosmetics than are genetics and training. People like to claim that abs are made in the kitchen, but the truth is that muscles are made by exercise. I’m pretty sure I didn’t get my sculpted legs and ass from eating kale salads; I got them from running 6 days per week for 33 years. And so it is for other runners as well.
This is not to say that a person’s diet doesn’t matter. Of course it does. But to place such a large emphasis on diet over exercise misses an important point—cutting calories and eating a more nutritious diet does not make you fitter. Although your nutrition is undoubtedly important, it doesn’t give your muscles a stimulus to adapt. Only exercise can do that and thus give you all of the fitness and health benefits. The sculpted legs of runners and upper bodies of fitness magazine models didn’t get that way just by eating fruits and vegetables.
Research shows that you need both diet and exercise. Diet gets your weight off, especially initially, and exercise keeps it off. To lose weight, you must consume fewer calories each day. To maintain weight, you must exercise on most, if not all, days of the week.
There is a ton of research to show that body weight and body mass index are directly proportional to the amount of exercise people do. If we take two people, and one eats perfectly clean with a nutrient-dense diet and no processed foods but doesn’t exercise much, and the other runs a lot and does resistance training but has a mediocre diet with the occasional Twinkie or chocolate chip cookie, who is going to look better and be fitter? I hope you said the latter. Truth is, exercise and genetics exert a greater influence on how you look (and on your physical performance) than your diet does.
For more information, pick up a copy of Run Your Fat Off.