Does Calorie Restriction Work For Fat Loss?

Recently one of my clients asked me what exactly is a calorie restriction and how it works.

So buckle up because in this article I will explain to you everything there is to know about calorie restriction, tips, and the benefits.

Calorie restriction is nothing else than reducing the number of calories in the diet to create a calorie deficit. It works by restricting calories and creating a cascade of metabolic changes that cause the body to use fat for energy, and over time, to lose weight.

But if that would be so easy, everyone would be walking around peeled with their abs displayed looking saucy all year round. But instead, over 80% of people who lost weight gain it back.

What exactly is calorie restriction?

Have you ever heard people talking about their new diet?

They may say things like “I’m a vegan”, “I’m doing a Paleo diet” or “Dr.X diet” or whatever. Recently I saw someone telling me they are on a calorie restriction diet and I almost fall off my chair.

Calorie restriction is not really a diet.

It means reducing food intake to the point where our total daily calorie expenditure, including physical and non-physical activity, is bigger than our calorie intake (food that we eat).

And by reducing the calorie intake and creating a calorie deficit, we lose weight.

And that will happen regardless if you’re on the ketogenic diet, paleo diet, or plant-based diet. If you’re eating less food, you’re restricting calories.

Benefits of calorie restriction according to research

I think the best way to illustrate to you the benefits of calorie restriction is by showing a few studies that highlight all the main key points.

Bear in mind that those are real-life examples of people, not a laboratory in vitro studies.

Also if you want to dig deeper into the science, I’ve included all the resources where I pull off the studies. So feel free to put on your researcher hut and learn more.

1. It may improve mortality

The most obvious example you can see is on the island called Okinawa near the Japanese mainland.

According to the Annals of the New York Academy of Sciences Journal, Okinawan’s lifespan (the number of years they live) on average is around 83.8 years, with a maximum number of 104.9 years.

According to the journal:

  • On average, Okinawans stay in a 10–15% daily calorie deficit. (Diet is low on protein and rich in fresh vegetables, fruits, potatoes, soy, and fish.)
  • Okinawans consume around 17% fewer calories than the average adult in Japan.
  • Okinawans consume around 40% less than the average adult in the United States.

The oldest article on restricting calories was written in 1920 by Mikkel Hindhede, a Danish physician and nutritionist.

(It actually written during During World War 1 in 1917, but it was only published in 1920.)

In this research, Danish men and women experienced a 34% reduction in death rates in due to calorie deficit. The main foods included whole-grain cereals, vegetables, and milk.

This is one of those studies that you wouldn’t be able to do today because people didn’t choose to do it voluntarily.

2. It may improve insulin sensitivity

According to article published in Diabetes Care Journal, people who were reducing their calorie intake (25% of calorie restriction) experienced 40% improvement of their insulin sensitivity after 6 months.

Insulin sensitivity relates to your efficiency of insulin to transport glucose away from blood to the rest of the body.

High insulin sensitivity means less insulin is required to do the job. Poor insulin sensitivity means more insulin is required.

“Calorie restriction by diet alone or with exercise is enough to reverse insulin resistance,” states the article.

3. It may improves body composition

A 1-year randomized controlled trial published The Journals of Gerontology documented two groups of people – group one reduced calorie intake by 20% and group two increased physical activity by 20%.

“After 12 months, all people from both groups (calorie restriction and exercise) reduced weight got similar results,” states the article.

Calorie restriction doesn’t always mean you have to eat less food. It can also means that you move more that usual.

And by adding extra exercise in any form, you increase your energy expenditure, without changing your diet.

Can you lose weight just by restricting calories?

According to recently published article in The New England Journal of Medicine, restricting calories is enough to trigger the body to lose weight.

The key element is the time and consistency. For weight loss to happen, it does takes time. So the best approach would be to not focus on which diet is better, but on how you can sustain eating fewer calories.

For me its always better to find ways to maintain a healthy lifestyle while being in a calorie deficit.

Those would include things like:

Managing stress levels without eating

If you use food to reduce stress you can have a never-ending loop of losing and gaining weight.

Stress eaters need to find different methods to regulate their emotions and stress.

Increasing physical activity, social interactions, getting a dog, traveling, and hobbies are all effective ways to reduce stress without using food.

Trying occasional intermittent fasting to improve hunger tolerance

Physical hunger is different than psychological hunger. People generally are afraid of feeling hungry.

The more often you reduce food intake, you may realize that its possible to be in a calorie deficit and get used to hunger.

Eating mindfully without distractions

The more you’re anchored to the moment and you’re not being distracted by watching TV, driving a car, or eating on the go, the you will more likely eat less because you can listen to your body signals.

Organizing the home and kitchen environment to support your goals

If food is in your house or your possession, sooner or later you will eat it. So mindful shopping and storing food that is not gonna trigger unwanted behaviors is the easiest way to succeed.

How to start a calorie restriction diet?

There are multiple ways to start a calorie restricted diet. In general, reducing calories from the total food you eat, adding extra exercise, or both.

Some of the best strategies include mindful eating, using a food plate as portion control, using a hand-size guide, or counting calories.

There are no better or worse ways to eat less food. It’s all about preferences. Just like when choosing the color for the car you’re buying. Regardless of which color you decide, the car will still drive and do its work.

Mindful Eating

Mindful eating is about being present in the moment and focusing on how you eat, rather than what you eat. What you eat is important but how you eat is often forgotten and ignored. This include thing like:

  • Eating slowly
  • Eating when you’re physically hungry
  • Eating till you feel no longer hungry
  • Eating without distractions

Using plates as portion reference

Using plates is a popular way to have a consistent reference point for what you eat. It works simply by dividing your plate into 3-4 groups and filling those spaces with the food you want. Things to consider:

  • It’s easy
  • It can be done by anyone (vegan, paleo, keto)
  • It gives you the same reference with each meal
  • It can be adjusted anytime

Using Hand-size as Portion Reference

Similar to plate reference, you can use your hand as a guide. The thickness of your palm is the protein portion. The full first is the number of non-starchy veggies. A handful is for starch, and a thumb is for healthy fats.

  • It’s easy and portable
  • It can be done by anyone (vegan, paleo, keto)
  • It gives you the same reference with each meal, regardless of the place you eat

Counting Calories

Counting calories is the most popular and known method. It is the most accurate, but at the same time, it requires so much more work.

You need to know your specific goals, calorie needs, and calories in each food. And frankly, the number of calories in foods may vary significantly, depending on many factors.

  • Its most precise
  • It’s done by professional athletes and actors to achieve desired weight fast
  • It can get you very lean

Things to consider before starting calorie restriction

People are not robots

Counting calories and meticulously measuring the food portions may be doable for the week or month.

But for the long haul, deciding whenever I’m gonna eat my favorite meal based on the amount of fat or carbs it has is not sustainable.

People are not spreadsheets

With some of the more advanced approaches like calorie counting you need to know exactly what you eat on the daily basis, make small adjustments, and track those adjustments (even as small as 50-100 calories).

That is one spoonful of peanut butter or olive oil. If you’re not committed to counting all of this, it may be hard for you to work otherwise.

People are different

A 20-year-old dude from YouTube who plays video games all day has different responsibilities in life compared to a 35-year-old single mom who is juggling 2 full-time jobs and looking after her sick mom.

People have their own limitations

Things like allergies, food intolerance, aging, GI health, muscle and joint pain, illness, and more. Those limitations are what make us unique.

That’s why choosing the calorie restriction method should be seen as an individual, not one-size-fits-all.

So when you choose to start a calorie restriction, you need to look at your lifestyle first, not what is most effective.

How much weight can you lose with calorie restriction?

On average, you can lose between 1-3 pounds per week on a well-balanced calorie restriction plan.

The amount of weight loss depends on things like age, gender, physical activity, lean body mass, total calorie intake, and other things that indirectly affect our food choices like stress and energy levels.

It doesn’t matter if you gonna be fasting or a typical calorie restriction.

The overall results come from being able to sustain long enough in a calorie deficit, and how each person is gonna do this will only depend on the preferences and lifestyle of the individual.


In summary, a calorie restriction diet is nothing else than just reducing your calorie intake.

It can be as simple as skipping a meal, not eating after 6 pm, counting calories, eating slowly, or all of the above. In the end, the most important thing about calorie restriction is your ability to do it long-term.

Michal Sieroslawski

Michal is an exercise physiologist (MSc) and a veteran endurance athlete. He loves to experiment and share his successes and failures to help busy men and women who want to lose weight.

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