Weight Loss
Protein Fasting for Rapid Fat Loss—Does It Really Work Long-Term?
Protein fasting delivers impressive rapid results—yet why do most people regain the weight? A critical look at one of nutrition's most abused concepts.
Weight Loss
Protein fasting delivers impressive rapid results—yet why do most people regain the weight? A critical look at one of nutrition's most abused concepts.
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In our new course, we devote an entire lesson to protein fasting.
Protein fasting is not about avoiding protein. Instead, it's a form of "fasting" with protein. This preserves lean mass and prevents an overly sharp drop in metabolic rate.
Protein-based weight loss was likely developed in the 1970s. It was during this period that the term protein sparing modified fast (PSMF) first appeared in scientific literature.
The protein-sparing fast, in other words. Since then, PSMF has been recycled nearly every year under a new name. We won't name them here—anyone who reflects a bit will recognize plenty of "new diets" based on this mechanism.
Many clever entrepreneurs simply put their name in front of "protein fasting" and made a lot of money—mind you, this has been going on for many, many decades.
Particularly prominent in the late 2000s, during the early Internet boom. Exactly how many people PSMF made rich is impossible to calculate, but it's certainly a lot.
That's all well and good. People who help others should earn money. Fair enough. But there's a small problem. "Help" should be something long-lasting, right?
Almost anyone can do protein fasting. The concept was originally designed to help severely overweight people quickly. The results are often strikingly impressive.
And: nowadays, protein fasting can be adapted to a fun lifestyle—much like veganism.
You can stock up on incredibly tasty protein powders, sweet-flavored powders to mask the otherwise bland taste of dairy products, and an array of low-calorie or zero-calorie replacement products.
And continue with what is, by definition, protein fasting. But that has nothing to do with healthy eating. In these approaches, people usually learn only how to lose weight quickly.
They don't learn how to keep it off long-term. Making that possible usually requires more than just using diet products to—literally—sweeten the day.
This reality shows up clearly in current research. Back in 2020, a landmark study of 1,400 participants followed for five years was published. The sobering result:
"Conclusions: In clinical practice, PSMF leads to rapid weight loss in the first 6 months, but only a small percentage of patients maintained significant weight loss over the long term."
Most people never hear about this. Many instead struggle into eating disorders because they assume they must maintain PSMF forever to keep experiencing fat loss.
Instead, after weight loss comes a need for reflection and change. Even a study from 1989 showed that "progressive reintroduction of carbohydrates" can substantially blunt expected weight regain and even produce positive effects.
Unfortunately, carbs are often deeply hated by those trying to diet.
Let's be clear: PSMF is frequently misused. Both by those selling it and by those using it to lose weight.
PSMF is not a toy. It's a very powerful tool that works with severe caloric restriction. Tinkering with it requires skill.
Especially in the context of modern diet products, PSMF is not a sustainable concept because it often leads to significant weight rebound. Hardly anyone talks about this—and those "after" photos certainly don't show up on social media anymore.
Worth knowing.
