Growing old is a thing of great concern, especially in today’s world. The thought of loneliness, diseases and even death that come with it make many persons try frantically to slow aging. There are numerous ways that have been suggested for achieving this goal. One of this is calorie restriction (CR). It has to be said that this approach is a controversial one, though. Some say it works while some others caution against it. In this piece, we shed light on what researchers know about the benefits and other things worth knowing, including possible adverse health effects.
What is calorie restriction?
The name practically says it all. Calorie restriction describes intentional efforts at reducing the amount of calories that are consumed. Also known as caloric restriction or dietary restriction, the regimen is ideally planned in a manner that ensures reduction in calorie intake does not result in malnutrition. This practice is normally observed for health and fitness reasons. Many people also practice it with the aim of slowing their aging clock. Research, mostly done using small animals, has confirmed these benefits as well.
Researchers have been examining how this dietary regimen could be beneficial to humans for about eight decades or so. But it is believed to have been in practice well before then. An example is the case of a 15th-century Venetian noble known as Luigi Cornaro. He is said to have practiced calorie restriction from age 35 to improve his failing health. This supposedly helped to eliminate his health worries and saw him live to a ripe old age of 102.
The book written by Cornaro detailing the method he employed contributed to make the dietary routine hugely popular during his time. This made him the first person to suggest this as an approach for enhancing longevity. But McCay and colleagues are believed to be the first researchers to prove this with their work in the 1930s.
There has been several studies since then aimed at knowing more about these benefits and others using animals. Human clinical trials are also being conducted by the U.S. National Institute on Aging (NIA).
How can it help with aging?
Better body composition
One of the problems that caloric restriction can help address is harmful effects of overeating. This constitutes grave risk to health. It is mainly a problem due to how it causes body fat to increase. A fact known by many is that cutting down on calories can help a person lose weight. This results in loss of visceral fat tissue, a serious concern in several medical conditions.
Researchers have observed that having excess body fat can shorten a person’s life. Excessive body weight or obesity raises the risk of having Alzheimer’s disease, diabetes, cancer and other conditions associated with older individuals. Dietary restriction helps to guard against visceral fat accumulation and intramyocellular lipid deposition that are characteristic of aging.
Reduced energy expenditure
Another way by which CR may help fight aging is that it reduces the amount of energy your body uses. Put differently, your body will not have to work extra hard to eliminate waste product generated from what you eat. It causes a decrease in energy metabolism, partly because of reduction in your energy intake. This may even enable you to make better use of the energy that comes from your food.
Lower oxidative stress
This potential anti-aging benefit of calorie restriction is connected to reduced energy metabolism. Research has shown that the dietary strategy helps to combat oxidative stress in different species, including mammals. There is correlation between lifespan, energy metabolism and levels of reactive oxygen species (ROS).
A proportion of oxygen used up in energy metabolism is accounted for by ROS production. This contributes to oxidative stress. Some scientists believe that the lowering of metabolic rate can therefore help to guard against oxidative damage. The idea is that as calorie restriction causes energy metabolism to reduce, oxygen consumption and ROS generation drops. This is believed to be capable of promoting longevity.
Enhanced autophagy
Researchers have observed that dietary restriction may help to boost autophagy, a cell repair mechanism. Autophagy is a process whereby damaged materials in cells are eliminated and replaced with new components. CR is believed to up-regulate this intracellular degradation mechanism by reducing the levels of insulin and related substances. With autophagy enhanced, your body may become more efficient at fighting aging. It will help to guard against accumulation of damaged cellular materials that could bring up issues associated to old age.
Gene expression aid
Much of the age-related changes that people experience appear to be as a result of modifications in gene expression. Research carried out on rodent, using DNA microarrays, linked aging to changes in brain, heart, and muscle gene expression. Scientists think that calorie restriction may serve as a shield against these alterations. It has the potential to reduce macromolecular damage and improve protein turnover. These actions are thought capable of slowing aging.
Reduced cardiovascular disease risk
It has been observed that this dietary restriction may help to improve your heart health. The risk of developing atherosclerosis is believed to be lower when observing the strategy. Research shows that this inflammatory condition results from endothelial dysfunction caused by factors such as free radicals, oxidative stress, diabetes and hypertension. CR may help to enhance endothelial function and thereby prevent atherosclerosis.
The diet could be beneficial in improving a number of risk factors for atherosclerosis. Evidence from rodent studies indicates that risk factors, such as low density lipoprotein (LDL), high density lipoprotein (HDL), triglycerides levels, c-reactive protein and blood pressure, are better in CR subjects, compared to those on Western diets.
In an experiment, subjects who observed strict caloric restriction for between 3 and 15 years were found to have better diastolic function than their peers who didn’t. They had less ventricular stiffness and diastolic recoil loss. All these mean that CR may improve the quality and span of a practitioner’s life.
Cancer prevention
It is also thought that caloric restriction may be beneficial in warding off certain types of cancer. It deals with several hormonal and metabolic factors that cause these conditions. These include body fat, inflammatory cytokines and estradiol.
How calorie restriction works?
One of the puzzles that researchers have been battling to resolve for many years is finding out how CR is able to deliver the benefits that are attributed to it. While progress has been made, it is not entirely clear how it actually does this.
Hormesis has been suggested as the likely mechanism employed to deliver these CR benefits. The dietary regimen causes low-intensity biological stress which puts the body in a defensive mode. This response may help to fight medical conditions that are associated to aging.
Another explanation that has been put forward has to do with moderated body temperature that the diet causes. When you reduce your calorie intake, your core body temperature falls. This reaction is a way of adapting to lower nutrient availability and to reduce energy that is used up.
Other studies have shown that sirtuin plays a role in how CR works. Silent information regulator 2 (Sir2) gene in particular is said to be a key factor how this dietary strategy is able to extend lifespan. Research shows that in the absence of this gene lifespan becomes shorter. This implies that sirtuin is the vehicle through which this regimen is able to enhance longevity.
Calorie restriction and growth hormone in anti-aging
Human growth hormone is now widely known to have the potential of helping to slow aging, just like calorie restriction. The amount of the polypeptide that a person has is considered a factor in how healthy and fit he or she will be. Is there a relationship between the two approaches to slowing aging? Does CR help to boost HGH levels?
Going by evidence from research, there is a connection between these two. Growth hormone appears to be a key factor in the ability of dietary restriction to extend lifespan. In a series of experiments, some researchers studied this link using normal mice and GH-deficient, mutant mice. The mutants lacked GH receptor and, as such, were resistant to the substance. While calorie restriction helped to extend the lives of normal mice, the mutant mice did not experience similar improvement. This was attributed to absence of GH receptor in the latter group of animals.
It seems there is no definite conclusion on whether CR may increase the amount of GH in the body. In a 1999 study by Rose and colleagues, short obese children showed improvement in mean night growth hormone levels following 24-hour calorie restriction.
But another study indicated that it was not really likely that calorie restriction may help you to have more growth hormone in your body as you grow older. Redman et al noted this in a study published in the journal Aging Cell in 2010. A 25% dietary regimen lasting six months failed to change GH levels in non-obese subjects. It produced no change in insulin-like growth factor-1 (IGF-1) either.
Tips for successfully observing CR diet
Does caloric restriction sound like something you want to try out? You need to be extra careful for you to achieve success with the strategy. Here are a couple of suggestions to help.
Monitor what you eat closely
It is important to maintain a healthy diet for CR to work. By this, we mean you should eliminate all junk foods that many people are forced to make do with in modern society. You should eat lots of fruits and vegetables. These mostly have low amount of calories while offering powerful antioxidants that can promote your overall health.
And when trying to reduce your calorie intake, it is helpful to pay close attention to what you eat. Get the calculation right when getting any food item from your local grocery store. A marketing gimmick used by some companies is listing calorie content by portion. You may easily fail to realize how much you are consuming because of this. You therefore need to put portion calculation into perspective. It may also help to get a guide on amount of calories each food item contains.
Go for the water
When on a CR regimen, the feeling of hunger is an issue you may have to deal with constantly. But the thing here is that food is not necessarily the solution every time the craving comes. A glass of water may be all you need to keep this under control in some instances. You can only think about eating after this if the hunger just won’t go away.
Consider supplements
It is likely that you may not be able to get all the nutrients you need from the food you eat when practicing dietary restriction. This is more likely to be the case when you maintain a very busy, active lifestyle. So it makes perfect sense to consider use of anti aging supplements to make up for nutrients you may not be getting enough from your diet.
Have the right attitude
You will benefit from having positive outlook and determination to succeed with CR. This requires that you do not look at this regimen as a punishment of sorts. You have to approach it in an unperturbed manner and work to stave off the element of frustration. Don’t give it all up if you find yourself regressing to your old eating habits. Just snap out of it and make effort to stay the course.
Some CR safety concerns
Before you decide to go ahead with caloric restriction, it is of use to know the risks that could be involved. This way you can do a comparison to the benefits to know if it is indeed worthwhile.
Malnutrition – There is risk of you becoming malnourished when practicing calorie restriction. Ideally, the diet is planned is such a way that malnutrition doesn’t set in. But issues could result when due diligence is not done in this regard. Resulting complications when this happens include anemia, weakness, muscle wasting, lethargy, and dizziness.
Extremely low BMI – CR helps to promote weight loss. But it is potentially capable of reducing body mass index (BMI) to a level that is way lower than normal. This increases the risk of mortality, especially among the elderly.
Musculoskeletal issues – Research indicates that calorie restriction could cause reduction of bone mineral density. It may also lead to loss of lean muscle mass and reduced strength. This is a greater concern to already lean individuals. In a 2007 literature review, researchers said even moderate calorie restriction constitutes a risk.
Individuals with binge eating disorder may experience aggravation of the problem with CR. Pregnant women, or those trying to be, are warned against practicing calorie restriction as it may result in infertility and premature delivery.
Calorie restriction offers the potential to help you slow aging. There is research to show that it may help prevent age-related issues among older individuals. Please note that guidance by your doctor will be useful before deciding to try this one out.
