Low-Calorie Diet Vs. Fasting- Which is Better?

Hi everyone and welcome back to ComputerFitness247, where today we are going to dive into the difference between eating less food and eating no food. To be more specific, we will be looking at how a low-calorie diet fares compared to traditional/modern fasting. Well without further ado, lets have a closer look shall we?

Case Study 1: Minnesota Starvation Experiment

In 1944, a study called the Minnesota Starvation Experiment was conducted and was designed to understand the effects of caloric restriction on the body in order to gain some knowledge that would help people starving in the aftermath of World War 2. 36 healthy men with an average height of 178cm (about five foot ten) and average weight of 69.3kg (153 pounds) were selected.

Come on man you can do it!

For three months, they ate a diet of 3200 calories per day. Then, for six months they ate only 1570 calories. However, caloric intake was adjusted to attempt to have the men lose 1.1kg per week, which meant some men got less than 1000 calories per day. The foods given were high in carbohydrates i.e. potatoes, turnips, bread and macaroni. Meat and dairy products were rarely given. During the six months, the men experienced profound physical and psychological changes. Everyone complained that they were too cold.

One subject talked about having to wear a sweater in July on a sunny day. The subjects’ body temperature dropped to an average of 95.8 degrees Fahrenheit (35.4 degrees celsius). Physical endurance dropped by half, and strength showed a 21% decrease. The men experienced a complete lack of interest in everything except for food, which they were obsessed with. They were plagued with constant and intense hunger. There were several cases of neurotic behaviour like hoarding cookbooks and utensils.

Two participants had to be cut from the experiment because they admitted to stealing and eating several raw turnips and taking scraps of food from garbage cans. At first, the participants were allowed to chew gum, until some of the men began chewing up to 40 packages a day.

Case Study 2: Angus Barbieri

Holds a world record even to this day!

Now compare all this to the case of Angus Barbieri, a Scottish man who in 1965 fasted for over 380 days straight. That is he took in no food whatsoever -nothing but water, black coffee and black tea for just over a year. He lost 276 pounds, going from from 456 pounds to 180.

A case report published by the Dundee University Department of Medicine in 1973 said “...the patient remained symptom-free, felt well and walked about normally,” and “Prolonged fasting in this patient had no ill-effects.” There were no complaints of mind numbing hunger and he kept the weight off- for several years his weight stayed around 196 pounds. This of course is not a perfect comparison, with the case of Angus, there’s only one subject and his starting weight was drastically higher compared to those in the Minnesota Experiment.

However, it does illustrate some very interesting points about just how different of a physiological response you get from fasting (that is, eating nothing) compared to eating less, or caloric restriction. Dr. Jason Fung, a physician specialising in kidney disease, and author of the Obesity Code, says that compared to fasting, Caloric Reduction will result in:

  • less weight loss
  • more lean mass loss (i.e. more muscle loss)
  • more hunger.

Case Study 3: The Fasting Cure

Let’s start by talking about hunger. In Upton Sinclair’s 1911 book “The Fasting Cure,” he writes about fasting as a means to improve health. In describing his first couple attempts at fasting he writes “I was very hungry for the first day-the unwholesome, ravening sort of hunger that all dyspeptics know. I had a little hunger the second morning, and thereafter, to my great astonishment, no hunger whatever-no more interest in food than if I had ever known the taste of it.”

One word: Legend

Sinclair recommends to do quite long fasts - around 12 days or so. In a section addressing concerns about fasting he writes:

“Several people have asked me if it would not be better for them to eat very lightly instead of fasting, or to content themselves with fasts of two or three days at frequent intervals. My reply to that is that I find it very much harder to do that, because all the trouble in the fast occurs during the first two or three days. It is during those days that you are hungry.”

Then he says:

“...perhaps, it might be a good thing to eat very lightly of fruit, instead of taking an absolute fast-the only trouble is that I cannot do it. Again and again I have tried, but always with the same result: the light meals are just enough to keep me ravenously hungry...”

In the book he says you will know when you should finish fasting, because your hunger will “return."

He quotes a letter he received from a 72 year old man saying:

“After fasting twenty-eight days I began to be hungry, and broke my fast with a little grape juice, followed the next day with tomatoes, and later with vegetable soup. ”

He quotes several other letters he received from readers and this disappearance and reappearance of hunger is a common theme. Everyone who wrote to him fasted for at least 10 days, saying they only broke their fast when hunger “returned.” This phenomenon runs contrary to the idea one would get hungrier and hungrier as long as they don’t eat.

Case Study 4: Ghrelin
Oh no, it's the dreaded hunger hormone!

However, most people have experienced for themselves that this is not the case. Some will find that they are not hungry at all in the morning or at least they are not as hungry as they are for lunch or dinner. But unless you are eating in your sleep, the morning is when you have gone the longest without food. Some of this can be explained by the hormone Ghrelin. Ghrelin, known as the “hunger hormone” has been found to increase appetite and weight gain.

A study concerning Ghrelin was done at Aarhus University Hospital in Denmark and it shows what happens if you do a longer fast. They looked at the Ghrelin levels of 33 subjects who fasted for 84 hours. So, did they get increasingly hungrier throughout the fasting period? Well, No. Their Ghrelin followed similar rhythms each day but actually decreased the longer they fasted. Going longer without food actually made them less hungry. But, it won’t get worse, the hunger will simply go away if you are patient.

I’ve experienced this kind of spontaneous decrease in hunger myself many times. Lunch time would come and I would be hungry, but I was too busy to eat so I just kept working and kept myself busy. Pretty quickly I forgot about eating and wasn’t particularly hungry until dinner time. This is very helpful to keep in mind if you’re doing a long fast or even if you’re starting intermittent fasting - you’re going to get annoying waves of hunger, especially around the times that you usually eat.

This supports what Upton Sinclair and his readers said about hunger disappearing after the first 3 days of fasting. I’ve done a 2 day fast in the past myself and I can say that my hunger pains was slowly decreasing. Another thing that may be contributing to this phenomenon is that you are entering Ketosis.

Ketosis: Weight loss' best friend?

Don't know about you, but that sure looks good :P

Ketosis is a physiological state where your metabolism switches to using primarily fat for energy. For this reason Ketosis is popular as a weight loss method, but it has many other benefits including better physical and mental efficiency. Ketosis occurs when you restrict carbohydrates down to 50 grams or less and you don’t eat too much protein.

Everyone’s body is a bit different so you might have to eat even less carbohydrate or may have room for more, but the recommended ratio of a Ketogenic diet is to get 5% of your calories from carbs, 25% from protein and 75% from good fat. A simpler way to enter Ketosis is just don’t eat anything for a long enough time. This is one of the major points in the difference between fasting and caloric restriction. I have a whole article dedicated to Ketogenic diets and the Ketosis phenomenon here.

The problem with the subjects in the Minnesota Starvation Experiment was that they were eating just enough to keep them out of Ketosis and keep their metabolism primed for burning carbohydrate (glucose), so they couldn’t use their body fat for energy. This explains a lot of things like why they were losing their strength and were very sluggish and cold. It also clears up why Upton Sinclair said fruit or light meals were just enough to keep him ravenously hungry and far weaker than if he had just eaten nothing.

Final Thoughts

So, just to sum all this up: compared to a conventional low-caloric diet, fasting means you lose more weight in the form of fat, you keep more muscle via the Ketosis effect, you have more energy, and you are less hungry. This subject is very close to me as I engage in regular fasts both religiously and just to keep myself fit and healthy. Comment down below your experiences on fasting or adopting a low-caloric diet to supplement your health and fitness goals. Once again friends it has been a pleasure to enlighten you all. Enjoy the rest of your day!