Your Metabolism

Your metabolic rate is what determines how many calories you use every day, it determines how many calories you need to maintain your current weight. It is a function controlled by your thyroid and is largely also a function of your muscle mass.

Muscle, unlike body fat, is metabolically active. Muscle needs energy (calories) just to exist. Every ounce of muscle is using up calories just by being in place on your body. Fat is not metabolically active, and although large amounts of fat are heavy to move around, just the existence of fat does not require any energy/calories.

So the more muscle you have, the more calories you use every day, and the higher your metabolic rate.

Couple this with the fact that fat is burnt within muscle. That’s right, when we breakdown fat, it is carried to the muscle cells where it is ‘metabolized’ within the muscle itself. Muscle tissue is like your furnace - the more muscle you have, the greater your ability to burn up more fat. The less muscle you have, then the smaller your furnace and you not able to metabolize as much fat. This is why men can generally eat more than women. They have more metabolically active tissue (muscle).

The more muscle you have the higher your metabolic rate, which means even if you are doing nothing, your body still needs more calories every day than someone with less muscle. Also, the more muscle you have, the greater your ability to burn up those fat stores.

Low intensity cardio turns you into a ‘efficient fat burning machine.’ When you get a car that is more efficient at burning gas, it's wonderful as you do not need as much gas to do the same journey. When it comes to our body burning fat, do we want it to become ‘more efficient?’ Do we want it to burn less?

Muscle is the only tissue on the body that burns fat, and whereas low intensity cardio does create some demand on muscle, it does not demand nearly as much of them as a high intensity activity. Furthermore, studies have shown that with prolonged low intensity activity, the level of Cortisol (our stress hormone) increases. Cortisol is catabolic - it can break down muscle !

We can see here the worst possible scenario. Burn minimal calories, condition your body to become efficient at conserving fat and also lose some muscle, thereby reducing the ability to burn fat. This is not good.

As a personal note here, I have over all my years heard so many times the tale of someone who is just going to do cardio to lose some weight before they start with the weight training, or the person that just wants to get a bit leaner, so will only do cardio. Resistance training is so important, it is fundamental to weight loss. I would go so far as to say if you had to make the choice between moderate cardio and resistance training for your weight loss goal, then hit the weights and hit them hard. The more muscle you have, the more fat you burn, even at rest. I realize some ladies are concerned that they will put on too much muscle, but again, in all my years as a personal trainer, I have seen this very few times.