hi
i am wondering if there is any difference between doing a 40 min cardio versus 2 x 20min sessions in terms of calories burned and EPOC

am guessing that in the extreme longer sessions are better eg 60 mins better than 6 x 10min sessions???

and is it true you should resist eating for hour after cardio if wanting to lose fat?

Longer sessions aren't necessarily better. This used to be the conventional wisdom, but with newer approaches to exercise, such as HIIT, it isn't the case anymore.

Basically, doing steady cardio for, say, 45 minutes WILL burn more calories during that time than doing a 20 minute HIIT session (basically high intensity running/cycling/stepping etc with short breaks inbetween). However, once you stop doing the steady cardio, your calorie burning rate returns to normal, but with HIIT it remains elevated for quite a few hours afterwards, meaning that the TOTAL calories burned as a result of that workout can be much greater than doing steady cardio.

Hope that helps!

Do not resist eating after cardio. It does not burn more fat. Instead you will typically lose more muscle, and that will hinder you in the long run. You should eat *something* as soon as you're able after exercise, even if it's just a couple bites or juice.