Will I lose muscle if I do intermittent fasting to lose weight? Combine weight training with adequate protein to increase muscle and reduce fat

Fasting for 24 hours three times a week is certainly not an ideal diet for muscle building, but there are many forms of intermittent fasting, will they all cause muscle loss? But we can't generalize it!

Fasting is one of the most popular diets in recent years. Its advantages are that it is convenient, easy to understand and leaves no room for ambiguity. "Stop eating breakfast from today on" and "Only eat dinner all day on Wednesday and Saturday". These two simple sentences can fully explain the key points of the 16:8 fasting method and the 24-hour fasting method twice a week. There is probably no diet that is easier to understand than this.

But there are always drawbacks. Fasting has always been questioned whether it will affect muscle growth or even cause muscle loss? In this article, I would like to make a few clarifications about fasting: Why do I dare to recommend intermittent fasting? Wouldn't not eating cause muscle loss?

The human body's response to hunger

To answer the question "Will fasting cause muscle loss?", we must first understand two things:

1. Muscles are vital to human survival. Our ancestors relied on them for gathering and hunting in the wild. No muscle, no food.

2. Because muscle is necessary for survival, the fasting human body will protect muscle from loss as much as possible.

In my previous book, Dr. Scott’s One-Minute Weight Loss Class, we discussed the section titled “Will Not Eating Carbs Cause Fat Gain and Muscle Loss?” 〉, when the human body faces a calorie shortage (see the figure below), it will initially consume glycogen to cope with the calorie shortage. After the glycogen reserves are almost used up, it will switch to burning ketone bodies, fatty acids and gluconeogenesis as the main energy source.

Such a clever design saves humans from the embarrassing situation of "sacrificing muscle to save brain". Before the fat tissue is exhausted, the body will try not to use its precious muscles. Otherwise, how can it have the strength to survive in a harsh environment?

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For example: Suppose I live in the cold north, and in order to survive the cold winter, I build a sturdy wooden house for myself. The house was furnished with all the necessary furniture (muscle) and was quite comfortable. The warehouse was also filled with firewood (fat) to serve as fuel for the stove. As a result, that winter was particularly cold. I was curled up on the sofa and shivering from the cold. I picked up an axe, chopped up the sofa and threw it into the fire.

What? ? Isn't that stupid? The warehouse is clearly full of fuel (fat), so why should we burn the sofa (muscle) which has important uses first? Neither natural selection nor I are that stupid (right)! !

Fasting human experiment: Losing weight without losing muscle

From the perspective of evolution by natural selection, the body has good reasons not to use muscle for fuel. So in the real world, is there any scientific research to support this? An article published in the journal Obesity in 2010 may be able to give us the answer. Scholar Bhutani recruited 16 obese adults for an 8-week fasting treatment. The "alternate-day fasting method" they used is as follows:

● Fasting day: 25% of the daily calories required should be consumed between 12 noon and 2 pm. No food intake is allowed at other times.

● Normal day: Eat whatever you want, when and what you want, with complete freedom.

In other words, on fasting days, the subjects had to endure an extremely low-calorie diet and eat within a fixed time.

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After eight weeks, Bhutani measured the subjects' body composition using a resistive body fat meter and found that they had lost an average of 5.4 kg of fat, but their muscle mass had not decreased at all (and even increased slightly). Losing 5.4 kilograms of pure fat without sacrificing a single ounce of muscle, what a dreamy fairy tale!

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In addition, the subjects' waist circumference, triglycerides, and low-density lipoprotein (bad cholesterol) all decreased significantly, which means that their risk of cardiovascular disease was improved.

Both eat less, intermittent fasting can preserve muscle

Although the above research seems intriguing, it is the exception rather than the rule. In order to avoid muscle loss while losing weight, I would still recommend friends who are losing weight through intermittent fasting to do any form of strength training, whether it's gym equipment, TRX, squats with dumbbells at home, or even hanging on the horizontal bar and doing push-ups in the park.

As of 2020, there are eight studies that have combined weight/strength training with intermittent fasting. Most of the subjects did not experience a significant decrease in muscle mass, and one study even allowed people to gain muscle and lose fat at the same time.

Many intermittent fasting methods have been criticized because their goals are not clear. Intermittent fasting is a "subtraction method" for body fat, not an "addition method" for muscle gain.

For an athlete who is looking to build the most muscle mass, regardless of weight class, lifting the most weight is his only goal. Abdominal muscles, lines, and blood fat mean nothing to him, so will intermittent fasting help him? Of course not! But for a bodybuilder (or anyone, really) who wants to maintain high muscle mass and low body fat, does intermittent fasting have a role to play? I believe there is.

Choosing the right tool for the right situation can achieve twice the result with half the effort. It is a big misunderstanding to choose inappropriate tools in inappropriate situations and then blame the tools for not being good enough.

Dr. Scott's 1-minute reminder

Fasting is a good tool to lose body fat and improve health. When combined with weight training and sufficient protein, fasting will not cause muscle loss, and can even help build muscle and lose fat!

This article is selected from Sancai Culture's "One-Minute Weight Loss Classroom 2 Dr. Scott's Scientific Guide to Muscle Gain and Fat Loss: The Latest Scientific Research X Seconds to Understand Chart Analysis, Debunking 41 Weight Loss Myths! 》