Fasting vs Calorie Restriction

[Daves_Not_Here]

This video describes the differences in outcomes between fasting and calorie restriction with references to the Minnesota Starvation Experiment and The Fasting Cure by Upton Sinclair written over 100 years ago.

[Dominique]

The video compares apples to oranges IMO. What he calls "calorie restriction" appears to be eating at a constant caloric deficit. As to fasting, many protocols are mentioned, in which the hiatus period when you don’t eat varies from several hours to many days (in the most extreme case, an obese person didn’t eat anything for over a year).

Why would people want to "eat less" (i.e. "restrict calories")? Well, most likely to lose weight. Should they fast instead? And since fasting is pitched against restricting calories, does it mean that fasting could lead to a better outcome (e.g. lose more weight) without even restricting calories? I don’t think so. If the aim is to fairly compare the impact of constant caloric restriction to that of fasting protocols, calories should be equated.

Let’s take three persons with an daily energy expenditure of 2000 calories. Person A will be eating 1500 calories every day (for good measure, spread over three evenly paced meals of 500 calories). The diet will last for 4 weeks (cumulative deficit: 500 x 7 x 4 = 14,000 calories). Person B will be eating 1750 calories 6 days of the week, and nothing on one day of the week (weekly deficit: 14,000 - 1750 x 6 =  3500 calories, so cumulative deficit over 4 weeks is also 14,000 calories). Person C will be eating 1500 calories everyday, like person A, but all during a single meal. What does the "science of fasting" say about this? Will it predict better outcomes for B et C? I personally think the differences (if any) will be very small.

Now what about macros? Let’s say A’s calories are 80% carbs, 15% protein and 5% fat, while B and C eat 80% fat, 15% protein and 5% carbs. I chose these on purpose, since proponents of fasting often favour low-carb diets, arguing it’s all about insulin. What are the expected outcomes? Well, studies show that if calories and protein are equated, there are no significant differences between low-carb/high-fat and high-carb/low-fat diets.

In a nutshell: timing of nutrient intake (e.g. fasting vs. multiple evenly spaced meals) is a matter of personal preferences. Same with mix of macros: you like fat, eat fat, you like carbs, eat carbs. 

[bikerhiker]

There are a number of fallacies and half-truths in the video; seemed like a diet propaganda view or a Ketogenic diet propaganda.

First of all, our body is built for fasting and it does it naturally when we sleep.  That is if we can consistently achieved stage 4 deep REM sleep, then your body naturally will use body fat as its fuel source.  It is when you are "NOT" achieving the required 7-8 hours of deep refreshing sleep is when you are not getting the benefits of fasting and your body isn't efficient in burning fat.

Which is why you have a new trend now, where you promote the body to fast on a regular basis.

All diet programs employ various methods of caloric restrictions to alter the body's function so it favours burning fat.  Note that I said "alters", because this is the current medical science thinking.  Whenever we have an illness, we treat the symptoms but not the cause of the symptoms.  So when we are ill, we take medicine.  So what is a medicine then?  A medicine can be a chemical/biological substance that can alter how your body functions to provide a therapeutic effect, but also comes with side effects and toxicity effects as well.  For example, Metformin is a common drug prescribed to Type 2 diabetic patients and while it helps managed diabetes by helping the liver reduce glucose production and helps muscles use glucose from the bloodstream (its therapeutic effect), its side effects are nausea, diarrhea and gas and Vitamin B12 and folic acid deficient plus you need good kidney and liver functions.  

Diets are like medicine as well.  They artificially alter the way your body use energy; mainly to focus on either burning fat or blocking the absorption of dietary fat when consuming food.  As with any methods which artificially alters the way your body works in using energy, it too has therapeutic effect as well as some side effects as well.  But this video only highlighted the side effect of a caloric deficit diet, but conveniently hide the side effect from a ketosis diet.

From the get-go, this video promotes a Ketogenic diet, because the main purpose of a Ketogenic diet is permanent fasting.  Basically, when you fast, the body will naturally go into ketosis when you starve the body off carbohydrates.  The body will then begin to use fat as its fuel source.  If you examine the urine of the person, the ketones level will be present as well.  However, what the video did not mention is that fasting is not weight loss.  Fasting is a quick rapid fluid loss, but as soon as you stop fasting and begin your normal diet again, you will gain your weight back as it is not permanent weight loss, which somehow the video conveniently did not disclose.  

This is the reason why, people who are in ketosis has to continue in ketosis; meaning that they have to artificially "force" the body to burn fat.  So when you artificially change how your body uses energy, you need to artificially create a diet to support this, which a Keto diet is based on.  Just like taking Metformin, you have to consume a Ketogenic diet based mainly on a high percentage of fat and a very low percentage of carbohydrates, so that you don't gain all your weight back.  And you need to take in this diet for the rest of your life if you plan to keep the weight down.  If you deviate from this diet, then there is a chance you will end your fasting period and the weight will start to come back.  So a side effect of a Ketogenic diet is the inflexibility of food choices and you also need  good liver and kidney.  Often, people go from taking Metformin and then getting off Metformin and into a Ketogenic diet and yet, this is simply shifting from one therapeutic process towards another therapeutic process.  But they are both still treating the symptoms, not addressing the cause of the symptoms, which is stress, unresolved past traumas and the inability to have a good deep sleep.  All of these can likely contribute to a higher chance of developing dementia later on in life.

To address the caloric deficit experiment.  You can see this in real time in Venezuela right now where their oil workers, unable to eat enough based a 2000 calories diet due to hyperinflation, are suffering the exactly the symptoms the video mentioned.

However, the video did not discuss the real issue of why there is a need to educate people consuming excess calories.  And the reason is that, Americans consume 51% processed foods which has way too much calories and little in nutritional value, which contributes to the weight gain epidemic.  Caloric restriction is basically to encourage people to adopt a healthy lifestyle and eat a healthy diet based on good amount of dietary fat, protein and carbohydrates for each individual needs to restore natural normal body function.  Weight loss will occur when the body is functioning at natural homeostasis and went the individual adopts a stress management better sleep process.  That is the basis of caloric deficit -- to stay away from processed food and refined sugar and not to starve yourself like the Venezuelan does right now.