Weight Loss Requires Caution: Rapid Weight Loss Leads to Rebound; Scientific Fat Reduction Preserves Muscle

Indeed, it is only natural to wish to lose weight quickly. Without proper knowledge of weight management, people often resort to extreme dietary measures—such as abstaining from food, starving themselves, or restricting certain nutrients—or engage in excessive, strenuous exercise.

Take dieting, for instance. While it may yield rapid weight loss, how long can one sustain such restrictive eating habits? Once normal eating resumes, increased food intake inevitably leads to regaining the lost weight.

Alternatively, dedicating hours daily to exercise might yield some initial slimming effects. However, this approach depletes both physical stamina and motivation. Once the exercise regimen is scaled back, weight regain follows.

What purpose does any of this serve?
Moreover, I'm sure you've all experienced this: the faster the weight comes off, the quicker it comes back on. Initially, the pounds may shed rapidly, but later on, even when eating very little, further weight loss becomes incredibly difficult. Conversely, eating just a little more causes the weight to rebound almost immediately.

Therefore, any method involving drastic dieting or excessive exercise is merely a temporary weight loss solution, unsustainable in the long term.

I have a childhood friend who's been perpetually dieting. Now he says he's given up. He's realised the more he loses, the easier it is to gain back. He's tried countless methods, each promising rapid short-term weight loss. After a brief triumph, he'd relax his diet only for the weight to rebound swiftly – often ending up slightly heavier than before.

Before dieting, he was merely slightly overweight. After years of trying various methods, he's now gained several sizes. When I saw him recently, I barely recognised him. He also mentioned that he used to be resistant to weight gain, but now he puts on weight from eating almost anything.

So why does rapid weight loss lead to such easy rebound?
Because extreme diets not only cause the body to shed significant amounts of water and sugar but also result in substantial loss of lean body mass. This loss of lean mass lowers the basal metabolic rate, reducing daily energy expenditure and consequently slowing down further weight loss.

Research indicates that when weight is shed solely through extreme dieting, 31% of the lost weight comprises lean body mass. Should weight rebound post-diet, even recovering half that lean mass means 15% was irretrievably lost during the diet. Muscle not only elevates basal metabolic rate but also burns more energy during exercise or activity.

In essence, rapid weight loss often involves shedding more lean body mass, yet subsequent weight regain predominantly consists of fat. Consequently, when the lost weight returns, it does not merely restore the initial weight but places the individual at a point worse than before. This represents not merely futile weight loss but negative weight loss.

This is because the altered body composition makes subsequent weight loss more challenging. With reduced lean body mass and increased fat proportion, the situation is more problematic than simple weight regain.

Generally, every 500 grams of muscle lost reduces basal metabolic rate by approximately 30 kcal per day. Losing 2.5 kilograms of muscle means the body burns nearly 150 fewer calories daily through basal metabolism alone – equivalent to a large bowl of rice.

Consequently, if muscle mass diminishes during weight loss, one must consume fewer calories to compensate for the reduced energy expenditure caused by this muscle loss.

Moreover, rapid weight loss depletes not only lean body mass but also the mass of internal organs. Take the liver, for instance: typically, only 100 grams of its protein can be broken down and utilised when dietary intake is insufficient. Moreover, the metabolic rate of internal organs is dozens of times higher than that of muscle. This means visceral tissue consumes more energy than muscle under normal conditions. Consequently, weight loss accompanied by a loss of visceral mass leads to a significant decline in basal metabolic rate and overall health.

Thus, the goal of healthy weight loss is to minimise lean body mass loss while reducing body fat. Otherwise, it amounts to counterproductive weight loss.

So how can one minimise lean body mass loss?
Firstly, control the rate of weight loss, ensuring the daily calorie deficit does not exceed 500 kcal. Secondly, increase protein intake to at least 1 gram per kilogram of body weight; for example, if you weigh 60 kilograms, ensure daily protein intake of 60 grams. Finally, incorporate muscle strength training throughout the weight loss period to maximise fat loss relative to lean mass.