The surprising science of water fasting (no food, no hunger)


If you’ve never done a very low calorie diet or even a pure water fast, you may have some trouble relating to this:

Science has proven that eating little to no food could actually be the key to getting rid of hunger and cravings, two major issues that annoy us heavily during just about any weight loss diet.

In other words, extreme diets like water fasting could ultimately be easier to handle than some of the way less restrictive weight loss diets.

And just for the record, I’m not writing this to convince you to go on some extreme diet, but because I think this really is an amazing phenomenon.

Zero food CAN equal zero hunger and cravings

In one study[1], they measured the intensity of hunger and cravings in two groups of people:

  1. A water fasting group (people in this group ate no food at all).
  2. A standard dieting group (people in this group ate a “balanced” weight loss diet).

And here’s the amazing thing that happened:

At the end of two weeks of going completely without food, the feelings of hunger and cravings dropped close to zero in the water fasting group. But in the standard dieting group, the hunger and cravings didn’t drop at all (they kept going strong throughout the diet).

One more study[2], in which people ate no food for as long as 117! days, also confirmed that “Hunger was virtually absent” during a water fast.

So no matter how hard that may be to believe, science has shown that the key to getting rid of hunger could actually be staying away from food altogether.

Now, let’s take a look at some of the diets that were less restrictive than water fasting (but still pretty restrictive).

A 400-calorie diet causes less hunger than a 1200-calorie diet

One study[3] compared a very restrictive diet (500 calories per day), to a “balanced” weight loss diet (1200 calories per day).

Even though people on the standard weight loss diet ate more than twice as many calories, they still reported stronger hunger than people who were on the more restrictive 500-calorie diet.

Another study[4] proved that a 400-calorie diet was able to reduce appetite, hunger, anxiety, and preoccupation with food in comparison to a balanced 1200-calorie weight loss diet (even though the diet allowed for three times as many calories).

So there you go. Against all common sense, modern science proves less food CAN mean less hunger.

Can any low calorie diet/fast reduce your cravings?

No, not exactly.

When it comes to hunger and cravings during rapid fat loss dieting, it’s not just about how much food you eat, but mostly about the kind of foods you eat.

So, unless you’re willing to completely give up food and do a pure water fast, low calorie diets will only decrease your hunger if you use a specific combination of foods.

We’re talking mostly protein-rich foods (not all of them will do the trick, but here’s a short list to get you started) and some other substances that have been proven to reduce appetite (like caffeine, for example).

But going into all the details would definitely be beyond the scope of this article.

The whole point I’m trying to get across here is, you should never dismiss a diet just because it seems too restrictive for you.

Or in other words, just because a food plan looks less restrictive on paper, that doesn’t automatically mean it will actually be easier to follow.

Does hunger really disappear 100% during water fasting?

Before I ever tried water fasting, I honestly thought I could never pull off something as extreme as going completely without food for days.

And when you try fasting for the very first time, things can get a little scary. Especially in those first couple of days, when you’re still transitioning into ketosis.

But once you get through that awkward first stage, hunger DOES become a lot easier to handle.

Now, this is just my personal experience, but once I get a few days deep into a fast, I sometimes feel like I no longer care about food at all. I literally feel like I could go on without food for weeks if I chose to.

But the truth is, even though water fasting can numb your hunger and cravings (while delivering insanely fast weight loss results), it certainly isn’t without flaws.

The number one problem with water fasting is the rapid destruction of “structural protein”, the basic building blocks of your muscles and vital organs[5].

So, while water fasting does have the amazing ability to virtually eliminate your hunger, I certainly can’t recommend it as a sustainable (long term) way to lose weight. But you can go here to learn more about a type of fast that was specifically designed to reverse that unnecessary destruction of your muscle mass and vital organ tissue.

Rok Sprogar, CNC, WLS
Rok Sprogar is a Certified Nutrition Coach (NASM-CNC) and a Certified Weight Loss Specialist (NASM-WLS) who has been writing actionable and science-based content at Leanhigh.