Yesterday at the gym, my trainer and I were surprised to see that my weight had dropped by a kilogram in just two days. But the good news ended there: my fat mass went up. It was mostly muscle loss.
My sleep was ok and what I had been eating was also normal. But upon closer inspection, he suspected that I had eaten too little that day (Friday). I did indeed eat rather less than the usual, especially at breakfast. I explained that it was due to a long day of endless meetings.
That was when he told me something that I found very startling: if you eat too little, your body will burn muscle first. Not the fat.
Apparently it has something to do with ancient biological survival instincts. If you eat too little, your body thinks you’re in trouble (like maybe the nearest food court is 20 km away), so it goes into starvation mode (read about it in the link). To protect its reserves (a.k.a. fat) it burns some fat as usual but also burns significant amounts of muscle mass, because, well, who needs all that extra muscle that needs so much energy and trouble to maintain, right? Stupid body… Your metabolism will also begin to decline as a survival response – and this is no good when you’re trying to lose weight.
I said that I’d always assumed it was the other way around, that eating less will cause more fats to burned for fuel – it seemed more logical.
This is an example of a snippet of bio info that few people really know and understand. Many people assume the “logical”, like I did, and end up causing their body more harm than good. Now it may be the case that it does not affect everyone, some even suggest it rarely happens except in extreme situations (true starvation situations) – but regardless of the validity, you should monitor your own eating and weight loss patterns, to figure out how it works (or not) on you. Something to think about.