It sounds like a simple answer of 'both', but I was wondering what people have actually found themselves when trying to lose weight (and let's face it - the vast majority of us have been there!) - has changing your diet or increasing your exercise level helped you more? Personally, I have managed to lose a fair deal of weight (10kgs, which is about 22 pounds) by changing to a low-fat vegan diet, but it looks like if I want to get rid of the last few stubborn pounds I will have to start exercising as well. Sigh. What have other readers found? Also make sure to check out this great infographic which actually breaks down the science behind successful weight loss.