calorie restriction effects on metabolism

Exactly How Calorie Restriction Affects Metabolism

Calorie restriction doesn't have to be be negative, but don't go in blind

Calorie restriction is a dietary regimen that reduces your daily calorie intake without any malnutrition.

In the past few years, the health trend ”less is more” has become popular and accepted.

But the concept has been around for a while. In 1935, Clive M. McCay and his colleagues introduced the concept of calorie restriction for the very first time.

Calorie restriction has been directly linked with an increased life span, but how does it affect your metabolism?

In this era where everyone is considering calorie restriction as a way to improve health status and rapidly cut off weight, you must learn the positive and negative calorie restriction effects on metabolism.


So, let’s address at first what is calorie restriction and why is it gaining much attention?

What is calorie restriction?

Calorie restriction improves your life span by increasing oxidative stress and lowering the chances of diabetes, heart diseases, metabolic disorders, neurological disorders, and cancer. 

This means if you wish for longevity you should choose calorie restriction.

Wait! There are still more insights into relevance with metabolism. So, here comes the question how does metabolism work under restricted calories? 

But at first, we need to understand how your metabolism works. 

Related: What to Drink When Fasting? 4 No-Calorie Drinks to Stay Hydrated

How does metabolism work?

Metabolism is a complex process in which your bodies convert the ingested food into energy with the help of oxygen. 

Have you not seen people blaming metabolism for their obesity? 

Yes, metabolism can be the culprit for your weight but it mainly depends on how you regulate it. Your diet habits and Calorie intake determines how your metabolism will work.

Your body needs the energy to perform the routine functions of breathing, growing and repairing, food processing and physical activities, etc. 

When you are at rest your metabolism is not at rest.

Metabolism works even at rest and its regulation depends on factors such as age, size, sex, and genetic makeup. 

But some scientists believe that the factors discussed above are not the ultimate factors and metabolism can be adjusted by avoiding poor dietary habits and inactivity.

Perfectly balancing the calories you take and burn is the key to longevity.  

Now, the main question is how do calorie restrictions manipulate the metabolism?

Dfferent forms of calorie restriction

  • Periodic fasting: Caloric restriction for several days and then normal eating (unrestricted).
  • Alternate fasting: Restricted eating on one day and then unrestricted eating on the next.
  • Time-restricted feeding: When you eat meals for some specified hours every day and then you do not eat in the rest of the hours.

Related: Intermittent Fasting for Beginners: Methods, Benefits, Precautions & Weight Loss

Calorie restriction effects on metabolism

Scientists believe that adequate calorie restriction with all the proper nutrients promotes better metabolism and ensures the least molecular damage.

Calorie restriction targets some specific molecular pathways such as PI3K/AKT, cardio-metabolic processes, lower TNF-α, Insulin, and oxidative damage in your body which directly help in anti-aging. 

Moreover, many examples from history predict how calorie restriction helped in increasing age and reducing health risks.

  •  It is reported that in World War 1 Danish population was forced to restrict their diet. Population received vegetable milk and cereals. The result was a decrease in their death rate.
  • In World War 2 in Norway, calorie restriction benefited the population of Oslo with a prominent 30% mortality rate decrease. That was a 20% calorie restriction without malnutrition and citizens were forced to eat fresh vegetables, fish, potatoes, and whole cereals. 

So, is this not interesting?

Human basic food needs are just these primary cereals and fresh natural foods so if you stop overeating and even restrict your calories it could go wonderful.

Despite all the research on the effects of calories restrictions on metabolism, there is still a huge void that needs to be covered with further research. 

There is not much data available on calorie restriction in humans but still, you can find a lot of volunteers who practiced this regimen and obtained useful results. 

Calorie restriction also shows a great influence on some other physiological patterns such as mood, sleep, sex and is supposed to improve the quality of life.

Does calorie restriction slow your metabolism?

Its answer is enigmatic due to the least scientific studies on Humans. 

You can find some studies supporting the hypothesis that calorie restriction reduces metabolism specifically basal metabolic rate.

Studies indirectly link the caloric restricted reduction in metabolism to reduced insulin, leptin, and thyroid hormone levels.

Calorie restriction induces quick weight loss by shifting your metabolism to increased gluconeogenesis and reduced lipid biosynthesis as CR increases fatty acid metabolism and β- Oxidation.  


There are no negative side effects of caloric restriction as per studies.

But yes, malnourished calorie restriction can lead to severe side effects so there is a stringent need to follow a well-maintained caloric restriction. 

Otherwise, be ready to face chronic weakness, bone weakness, reduced aerobic, psychological problems including; emotional upset, hysteria, depression, loss of sex drive, and many more. 

This argument is highly supported by the Minnesota Starvation Study

Currently, the scientific community is just not finding new insights into calorie restriction.

Instead, they are paying great attention to its alternate forms one of which is intermittent calorie restriction.

Hence, you have to choose which method is more reliable in the calorie restriction theory of aging.

Most of US guidelines favor continuous Calorie restriction but nowadays most people find it easy to practice intermittent fasting or calorie restriction instead of consistently reducing their daily intake. 

Some studies consider intermittent fasting more effective in altering the metabolism but at the same time, data from many other studies support that both the calorie restriction regimens work with almost the same efficacy.  

Nonetheless, Calorie restriction is a gold standard technique in anti-aging theory. It is an effective non-pharmacological remedy to combat metabolic syndromes.


Think of syndromes like hypertension, insulin resistance, and dyslipidemia. Also, calorie restriction may improve the life span.

Overall, Caloric restriction aims at providing an adequate intake of all necessary macro and micronutrients with restricted energy values.

This helps to promote longevity by reducing Insulin, thyroid, and leptin levels.


Calorie restriction is a wonderful regime to improve health, ensure longevity, and control obesity, diabetes, and cardio-metabolic diseases. 

We’ve discussed the effects of calorie restriction effects on metabolism. These effects include slowing down the metabolism, enhancing weight loss, and increasing human life span. 

You can opt for calorie restriction as a habit to improve your life!