Exercise and Bodyfat

Whole Health Source: Exercise and Bodyfat

I think it's clear that the relationship between exercise and weight is not very tight. In my opinion, diet has a much larger influence on weight than exercise. Doing low-intensity "cardio" on a treadmill is almost totally ineffective for weight loss.

So can exercise help a person reach or maintain a healthy weight? Absolutely, but the type of exercise is critical. Exercise plugs into some of the same metabolic pathways as a healthy diet, normalizing hormone levels and increasing stress resitance. All you have to do is pop over to Chris's Conditioning Research to see a number of studies that compared chronic cardio (as Mark Sisson would say) to high-intensity, intermittent training (HIIT). HIIT is the winner every time by virtually every measure. Even though a person burns fewer calories sprinting on and off for five minutes than she does running for 30, she will still lose more fat and gain more muscle sprinting because of the metabolic shift that type of training produces.

In one study Chris posted, investigators compared the effect of two different exercise styles on fat loss and metabolic parameters. One group was assigned to low-intensity steady-state exercise, while the other was assigned to short 8-second sprints (called HIIE in this study). Here's what they found after 15 weeks:

Both exercise groups demonstrated a significant improvement (P less than 0.05) in cardiovascular fitness. However, only the HIIE group had a significant reduction in total body mass (TBM), fat mass (FM), trunk fat and fasting plasma insulin levels.

I think exercise is part of the fat loss / maintenance toolkit, along with intermittent fasting.

But nothing beats a good diet.