Slow metabolism and starvation mode

Why does a very low calorie diet slow down weight loss (fat loss)?

Your body goes into starvation mode. This is a defence mechanism, evolved against starvation.This is to protect its fat storage, and instead use muscle for energy. This directly leads to a loss of muscle, which lowers metabolic rate so that the body needs fewer calories to keep ticking over and weight loss slows down. Of course, this is the perfect solution if you’re in a famine situation. But if you’re trying to lose weight, it is a failure.

How many calories should I have to prevent starvation mode?

Unfortunately, there’s no single answer to this question. Everyone’s metabolism is different, but everybody starts to use muscle to provide it with calories in a starvation mode.I recommend never going below 1,200 calories a day for women and 2000 calories for men, but it is way more complex than that:

  • Gender
  • Age
  • Bodytype
  • Lean mass
  • Exercises
  • Hormonal panel
  • Etc…

What’s the link between muscle and metabolism?

The metabolic rate is partly determined by the amount of muscle we have. In general:

The more muscle = the higher our metabolic rate

The less muscle we have= the lower our metabolic rate

This explains why men, who have more lean mass, have a faster metabolism than women, and why a young person has a higher metabolism than a old person, because young people have more muscle.

Muscle burns more calories than fat, so when we lose muscle, our metabolic rate drops and we burn less calories. Study shows that the body loses a lot of of muscle with a very low calorie diet and this may drop metabolism by up to 40%.

It’s crucial to protect your metabolic rate, especially when you’re dieting. And this means change your lifestyle, rather than a very low calorie diet, so that you lose fat rather than muscle.

Is there anything else I can do to stop losing muscle when I’m dieting?

Absolutely, stop dieting and make a permanent change with a healthy nutrition. Make sure you have enough calories to burn fat rather than muscle, it’s also possible to build muscle, which boosts your metabolism. Increase the amount of weights you lift. Proper weightlifting help to tone muscle and burn fat ( Hire a good personal trainer/nutrition consultant is crucial), it will also increase the amount of muscle. And this is good news because for every extra 1lb of muscle you have, your body uses around an extra 50 calories a day! This means an extra 10lb of muscle will burn  an extra 500 calories a day without you doing anything ,and that’s a sufficient amount to lose 1lb in a week.

Does your metabolism drop when you lose weight?

Yes, your metabolic rate naturally may slows down a little, but not necessarily if you gain a lot of muscle. When your body has less weight to carry around, it needs fewer calorie. This is why you should regularly update your Goals and Results ( muscle loss, muscle gain, bodyfat. intensity of weightlifting)

Will yo-yo dieting have damaged my metabolism permanently?

Fortunately not! The idea that yo-yo dieting permanently lowers your metabolism is simply not true. However, if you’ve frequently severely restricted your calorie intake without liftging weight, it’s likely you’ll have a lot less muscle now compared with the very first time you dieted. As a consequence, it’s likely your metabolism will also be lower so that you need fewer calories to maintain your current weight. This is because when you follow a very low calorie diet, you lose more muscle than fat. But when the weight goes back on, you usually only regain fat. This means, your metabolic rate  have dropped a little every time you’ve dieted, making it slightly harder each time for you to lose weight. The good news is you can increase the amount of muscle you have by a proper weightlifting.

For more on how to boost your metabolism, see my related article, my 8 principles for healthy aging

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