Move It & Lose It with Prof Trim

Lift it and shift it
‘While I regularly go for a walk, and even sometimes go the gym for a light aerobics class, my gym instructor keeps trying to talk me into lifting weights. Is there any real reason why I should do this when all I’m after is some weight loss.’

Sounds like you might already be doing the weight lifting, with the extra weight you’ve been carrying around (no offence meant). However, putting that aside for a minute, let’s look at any possible advantages you may get from doing resistance training (which, incidentally, doesn’t have to mean lifting weights).

There’s little doubt that the best type of exercise for long-term weight loss is endurance (aerobic) exercise. This is where most fat energy is likely to be burned over the least amount of time. Endurance exercise where you are carrying your own body weight (such as walking), is also better than that where the body weight is supported (such as swimming or cycling). However, once you get to a certain level, it may be appropriate to look to something different.

Put it this way: Let’s say you start at around 100 kg and walk for 1 km. You might burn up let’s say 100 kcals of energy doing this. If you do it daily for several weeks, your weight might begin to drop, for example to down around 90 kg. Now, not only because you are lighter, but because you are fitter, it takes less effort to carry your body frame over the said 1 km. In fact it may only require 80 kcals, making the energy loss disproportionate to the effort involved. You would then plateau and stop losing weight.

You can do a number of things to break through this: You can go back up to 100 kg by carrying a 10 kg back pack, adding more energy to the effort. Or, you might change the type of activity to introduce some resistance exercise. This not only changes the effort, but can help maintain metabolic rate while your total body mass decreases (through decreased body fat). Hence you maintain muscle while losing fat.

So, while resistance training may not be recommended while you are still big (you’ll want to lose total mass as well as fat), your instructor might be providing some useful advice to get you to try some resistance work as you start to slim down. It can also make you stronger, which may be of value in normal daily living.

Dr Garry Egger aka Prof Trim

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