Over the past year or so I’ve been learning about strength training and nutrition and I love what you guys are doing and appreciate your work. Recently I’ve been talking to some friends and family who are interested in weight loss and I try to help them with my limited knowledge. I talk to them about needing to be in a calorie deficit to lose weight, but it seems like they put too much emphasis on cardio and neglect the idea of calories in vs calories out. Some of them tried to explain to me that they need to do cardio to get their heart rate into a fat-burning zone. Is the “fat-burning zone” a legitimate concept or is it just from mainstream fitness? Isn’t the goal of cardio in terms of weight loss to put yourself in a further calorie deficit or to give a little extra wiggle room to eat more calories? Am I missing something? Thanks
The idea of a fat-burning zone is based on the differential use of energy stores during exercise based on exercise intensity. For example, when intensity is < 60-70% of VO2Max for aerobic activity, the predominant fuel substrate is fat. If it’s higher than this, it’s predominantly glucose. That said, none of this is relevant to energy balance and body composition changes so…it is, essentially, a TWOUD (time wasted on useless detail).
The main functions of aerobic training are to improve cardiorespiratory fitness, burn extra calories, and improve adherence to other lifestyle changes.