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Very Low Calorie Diets - More Harm Than Good

29 May 2022

It's time to stop trying diets that do more harm than good.

The year is 10,000 BC, a time when sabertooth tigers and wooly mammoths are still walking the earth. Humans lived in small tribes, and survived off of a hunter and gatherer lifestyle. The men would traditionally hunt, while the women would gather berries, fruits, plants and other food sources that they could find. Food wasn’t a guarantee, and no one ever knew for sure when they would have their next meal.

Luckily for the human race, our bodies are experts at preserving energy so we can stay alive when times are hard. Our resting metabolic rate is the number of calories we burn while we are sleeping, resting or not moving. Commonly referred to as our metabolism, this has the ability to be turned up or down, depending on whether food is scarce or plentiful at the time. 10,000 years ago, this was integral to the survival of the human race. Unfortunately, the evolution of our bodies has yet to catch up with our current lifestyles where calorie rich foods are readily available. As such, it continues to be easy to turn down our metabolisms, but much more challenging to turn our metabolisms up.

Why is this important? Our resting metabolic rate determines the minimum number of calories we need a day to maintain our weight. If your resting metabolic rate is higher, you burn more calories on a daily basis when you’re doing absolutely nothing. If it’s lower, you need to eat significantly fewer calories than another person in order to maintain your weight.

Thanks to evolution, when you starve your body for calories it goes into survival mode and turns down its metabolism. A modern day example of this is the popular TV show from the 2010’s called “The Biggest Loser”. Contestants would go on very low calorie diets and exercise in order to lose weight. And it worked! Of 16 contestants who participated in a scientific study during their time on the show, they lost an average of 128 pounds. However, this weight loss came at a cost.

During their time on the show, these contestants on average decreased their resting metabolic rate by 600 calories a day. That means in order to continue losing weight, they had to eat 600 fewer calories a day than they did prior to joining the show. Six years later, well after the show ended, the scientists who conducted the study followed up with the contestants. Six years after the show was over, the contestants had gained back 90 pounds of the weight they lost. Despite this, their basal metabolic rate was 700 calories lower than it was before they started the show. That was even lower than it was when they were on the show!

We have heard from our patients time and time again the same story:

" I did one of the very low calorie diet plans for 6 months, and during that time I lost 60 pounds. But the diet wasn’t something I could keep doing, and when I stopped the diet I gained back all the weight. And I didn’t just gain back the 60 pounds I lost, I gained an additional 15 pounds on top of it”

 Why is this? Because they significantly decreased their basal metabolic rate while on the very low calorie diet. When they started eating a normal diet again, their body immediately began storing the extra calories as fat. And it continued to do so. Our bodies still think it’s 10,000 years ago, and our body is worried that soon there won’t be enough food and it wants to store every calorie it can for when that day comes. Even though the diet works initially, it sets your body up for long term weight gain when you return to a normal diet.

That’s why we specifically recommend against very low calorie diets. Diets of 600 or 800 calories a day will lead to rapid initial weight loss, but this is not sustainable life long for most people. Rather than looking for the rapid, short term fix, we focus on strategies you can use life long to steadily lose weight and then maintain your goal weight. Through intermittent fasting you decrease your daily insulin spikes (which in turn leads to less fat storage). And through exercise and building lean muscle, you can increase your basal metabolic rate. This allows you to eat more calories, not less, and maintain your goal weight in the future.

Before you consider a very low calorie diet, pre-packaged food based diet or other “fad diet plans” out there come sit down with Dr. Katherine Dietrich to talk about other strategies that are going to work better in the long term.