One Meal a Day and Rejuvenation

One Meal a Day and Rejuvenation – Overview

One meal a day (OMAD) is an intermittent fasting technique used mainly to lose weight. Intuitively, OMAD consists of a period of approximately 23 hours of fasting and a meal adjusted to the energy and nutritional requirements of the individual.

In recent decades, investigative efforts have been made to discover the benefits of calorie restriction and its impact on health and disease.

Some of the underlying processes of aging and how calory restriction could be a tool used to delay it are coming into the awareness of several groups of scientists.

In this article, we are going to offer a quick review of some of the causes of aging and how OMAD would be a powerful tool to counteract this process.

The aging process results mainly from the consequences of the cell’s metabolic processes  

The purpose of an organism is to keep itself alive by a specific set of mechanisms. Animal cells use fuel from the environment mainly from three types of molecules: proteins, lipids (fats), and carbohydrates, also grouped under the concept “macromolecules”.

There is a cost to producing energy. Think of a car’s engine: the sparkplug initiates the combustion of fuel, consuming oxygen and generating a great amount of potential energy and heat, which impulse several mechanisms involved in the production of motion.

An analogical process is produced in the cell. The mitochondria, the cell’s “powerhouse”, take up the end-products of the processing of macromolecules to impulse several mechanisms that produce energy in the form of ATP by a set of reactions that include oxygen molecules.

The reactions result in the generation of reactive oxygen species, which are unstable atoms that promptly need to react with some other molecules.

ROS reactions usually damage several parts of the cell, as in the car, the parts suffer from wastage.

In the case of cells, this damage usually involves DNA molecules, proteins, and membranes, each of them involved in critical processes needed for living.

The accumulation of damage over time manifests in our bodies, making us weaker and more prone to disease.

Changing eating habits results in a metabolic switch

This concept refers to the changes produced at the cellular level that occur when switching to caloric-restriction dieting.

When we eat, our pancreas secretes insulin, a hormone that stimulates the use of glucose as metabolic fuel. If glucose exceeds the energy requirements of the body, then insulin signaling helps them save it in the form of glycogen in the liver and muscles and in the form of fat in adipocytes.

Insulin also stimulates the production of several proteins involved in carbohydrate metabolism.

The attachment of insulin to its receptor triggers a series of reactions called “second messengers” that modify the way our genes are expressed, increasing the synthesis of several proteins involved in carbohydrate metabolism and promoting cell growth. Therefore, we call insulin an “anabolic hormone”.

When fasting, the cells progressively change the way they use energy

On the other hand, when we fast, glucose levels are stable thanks to the action of the so-called insulin counter-regulatory hormones. The main hormone from this group is glucagon, another endocrine pancreatic hormone, and several others, including growth hormone, cortisol, and catecholamines.

The fasting state induces these hormones to be released and produces several changes in the cells depending on the target tissue. Glucagon stimulates the breakdown of glycogen in the liver, producing more glucose to maintain normal blood levels.

In the adipocytes, triglycerides are broken down into fatty acids that are transported to the liver and muscles to produce energy.

When glycogen is no longer available, the liver starts creating more glucose from fat and several amino acids, and further, it triggers the synthesis of ketone bodies from fatty acids. Ketone bodies are then used in most of the cells to produce energy.

One Meal a Day and Rejuvenation

One Meal a Day and Rejuvenation – How Does it Work

Different fuels are used at differing times

  • In a range of 1-3 hours after a meal, the body relies on the energy that food has provided.
  • In the next 3-8 hours, the liver takes the lead and breaks down glycogen into glucose, then this is transported in the blood to the rest of the body.
  • After about 8-12 hours, gluconeogenesis (the production of glucose from other sources) and ketogenesis begin.

The cell experience beneficial outcomes when the body is deprived of food

When our body energy expenditure depends mainly on ketone bodies, a state called ketosis, several changes occur at the genetic level and cells start to produce proteins involved in fat and ketone body metabolism, protection from oxidative stress produced by free radicals, and re-usage of dysfunctional cell components, a process called autophagy.

By repeating this whole process every other day, cells start to adapt to this new state using energy metabolites more efficiently, building strong defenses to free radical damage, increasing protection and stabilization of enzymes for metabolic processes, and providing streamlined recycling of damaged parts. In other words, we are slowing down the process of aging.


One meal a day is an intermittent fasting technique. It gives us a more resilient body able to overcome the daily “molecular” threats.

Most people on this regimen experience stable energy levels during the day, enhanced exercise tolerance, better sleep, and some improvement in mood and cognition.

If you are interested in this fascinating technique, be sure to talk to your doctor and dietician to evaluate if you are ready for OMAD and remember to complement it with a diet that fulfills your daily nutritional and energy requirements combined with a personalized exercise routine.

See Also

Blood Type Diet

Low Glycemic Index Foods List PDF

16/8 intermittent fasting 7 day meal plan

Pescatarian Diet

1200 Calorie Diet

Sirtfood Diet Food List

Current Version
September 4, 2022
Written By
Franco Cuevas, MD

Baynes J. W. & Dominiczak M. H. (2019). Medical biochemistry (Fifth). Elsevier Health Sciences.

Liguori I, Russo G, Curcio F, Bulli G, Aran L, Della-Morte D, Gargiulo G, Testa G, Cacciatore F, Bonaduce D, Abete P. Oxidative stress, aging, and diseases. Clin Interv Aging. 2018 Apr 26;13:757-772.

Rafael de Cabo, Ph.D., and Mark P. Mattson, Ph.D. Effects of Intermittent Fasting on Health, Aging, and Disease. N Engl J Med 2019; 381:2541-2551