Wanna know the KI(WI) to good health? Eating WELL. Everyone knows that eating "whole foods" is better for you than eating processed foods, but if you stop to think about it, do you know WHY (beyond the fact that processed foods are nutrient poor)? Here's the way I like to think about it. Think of processed foods as partially digested for you. Your body doesn't have to work as hard to break down processed foods as it does whole foods like fruits, vegetables, and nuts/seeds/grains.
My favorite example of this is peanuts vs. peanut butter. In this 2008 study, men were fed the same caloric content of peanuts (unprocessed) or peanut butter (processed). Both of these foods are high in fat. Researchers compared the amount of fat that was excreted from feces from these groups. The amount of fat that was excreted was greater in the group that ate whole peanuts compared to the group that ate peanut butter, meaning that even though the two groups took in the same calories (peanuts or peanut butter) they did not actually absorb the same calories.
The group that ate the whole peanuts absorbed less calories from those peanuts because some of it was excreted due to the fact that peanuts are uber tough to digest. Any time you eat something processed, you can pretty much guarantee that your body will absorb all of it. When you eat 200 calories of delicious PB, you will absorb 200 calories of delicious PB. When you eat whole food, however, your body has to work really hard to break that food down and even then, there are some pieces that will still pass right on through...you know what I mean. You've seen it. So, eating 200 calories of peanuts may mean that you actually only absorb 160 of those calories.
I always recommend clients get the diet figured out first before worrying about the exercise side. Exercise is an hour of your day. What you're eating the other 23 hours of the day is going to have a much larger impact on energy balance than the workout. Knock out getting nutrition right before you worry about knocking out push-ups. I love peanut butter so much.
Reference : Peanut digestion and energy balance. Traoret CJ, et al. Int J Obes (Lond). 2008.