A weight loss trend which is gaining popularity these days is the yo-yo-diet or crash diet which focuses on restricting energy to very low levels and starving the body to enable it to use up its stored fat.
In one phase, the person loses too much weight by limiting calorie intake and in other stage stops this diet and regains weight.
This is also called weight cycling.
Weight management is the primary concern for many individuals nowadays.
People not only want to lose weight and treat obesity but also want to achieve a healthy body weight and desired body shape.
For this, they opt for various kinds of weight loss regimes, exercises, and dieting.
One such type of dieting which is gaining popularity is crash dieting or yo-yo dieting.
What is a crash or yo-yo dieting?
Crash dieting or yo-yo dieting is a type of dieting in which calorie intake is restricted to promote weight loss for a short period.
This diet focuses solely on energy restriction to lose weight quickly without putting on any other efforts, exercise or physical activity.
This type of dieting was termed as yo-yo dieting by Kelly D. Brownell from Yale University. In this, the person loses and gains weight quickly.
This is also referred to as weight cycling wherein one cycle a person loses too much weight and then regains some weight, which resembles the up and down motion of a yo-yo.
The calorie intake is severely reduced to a few calories per day.
Usually, carbohydrate intake is reduced due to which the body does not get enough energy from the diet as is required by it on a daily basis.
As a result, the body starts deriving energy from the stored fats and carbohydrates in the body which lead to fat burning and a reduction in body weight.
Carbohydrates are usually stored in the form of glycogen.
Glycogen storage requires much water. While crash dieting, this glycogen starts to get utilizing, and the water with which it was stored is also lost by the body.
The body goes into starvation mode.
Crash dieting promotes faster weight loss but this effect this short-termed.
Though very effective, this type of dieting has serious side effects, and it is not considered good for health.
The general mechanism and working of the body are interrupted, and the body becomes susceptible to many deficiencies and disorders.
The nutrients received by the body in crash dieting are inadequate for the proper functioning of the body.
Here we discuss the many side effects of crash dieting and see how they adversely affect the health
8 Side Effects of Yo-yo / Crash Dieting
Below mentioned are the adverse effects of yo-yo or crash dieting on health.
1. Yo-yo diet lowers metabolism
Calorie restriction for a long time decreases the basal metabolic rate. The metabolism is reduced to match the low energy intake.
Due to lower food intake, the body does not need to digest more food and hence reduces its metabolic action.
Even after resuming eating, the metabolism remains reduced, and the body is unable to utilize the nutrients properly. Also, after the starvation phase, it starts to concentrate on storage of nutrients rather than their efficient utilization.
Reduced metabolism increases the risk of metabolic syndrome and other abnormalities.
In a study, it was found that women who undergo weight cycling or yo-yo dieting regularly have a higher chance of developing abnormal or disrupted metabolic profiles.
What does this mean? The metabolism rate of the body lowers in crash dieting and remains diminished even after the diet pattern is ceased.
2. Crash dieting weakens bones
When the calcium and vitamin D intake is not enough, the body starts using the calcium from the bones which make the bones weak and fragile leading to the susceptibility to develop fractures and diseases like osteoporosis.
In studies, it was found that restricted eating practices lead to a decrease in the bone mineral density and bone mass in women and are supposed to cause bone disorders like osteoporosis.
Also, regular increase and the decrease of body weight weakens the bones and causes the development of many diseases including fractures.
What does this mean? The decrease in proper nutrients like vitamin D and calcium can weaken bones and cause osteoporosis.
3. Yo-yo diet leads to higher body fat and more weight gain over time
Weight cycling has been found to result in higher body fat percentage.
In animal models, it has been proved that regular increase and decrease in body weight leads to more body fat deposition by energy restoration mechanism of the body.
An increase in body fat accumulation and the fatty tissues has been reported as a result of weight cycling in a variety of studies.
Dieting results in a reduction of both body fats and muscle mass. As a method of recovery from energy starvation, the body starts accumulating fats faster for later use.
Individuals who have lost weight by dieting had a lower metabolism and increased recovery of fats which contribute to weight regain.
Due to lowered metabolism, they are unable to metabolize various nutrients properly, which then gets deposited as fats in the body.
Long-term studies have shown that one-third of the individuals who lose weight by dieting regain more weight than they previously lost.
Restricting energy intake activates the body’s anti-starvation mechanism due to which the body aims at restoring the original body weight by regular and nutrient storage.
What does this mean? Over a long time, weight loss by yo-yo dieting can lead to more fat storage in the body and more weight regain.
4. It causes muscle loss
In crash dieting, energy intake is restricted up to a level of starvation. Starvation not only lowers the body fat concentration but also reduces the muscle and organ mass from the body.
This is because the body tries to compensate the deficient nutrients, by obtaining it from some organs and skeletal muscles.
It is not necessary that weight loss by calorie restriction will reduce body fat only. It can reduce both the fat mass and lean body mass. This can reduce muscle mass and durability.
It also reduces the muscle strength and leads to fatigue and weakness.
What does this mean? Crash dieting can decrease muscle mass and muscle strength.
5. It increases the risk of diabetes
A study published in The International Journal of Obesity states that yo-yo dieting leads to increased fat deposition and leads to the development of metabolic syndrome and type 2 diabetes.
This kind of diet which involves short-term food restriction increases insulin sensitivity, which is a risk factor for diabetes.
In women, regular variations in weight were associated with a higher risk of many diseases like cancer, stroke, fractures, and diabetes.
In animal models, diet cycling was found to increase insulin levels which are considered a precursor for the occurrence of diabetes.
In individuals who are already at risk of developing diabetes, weight loss by restricted calorie-intake leads to fat deposition and metabolic abnormalities and has long-term detrimental effects on health.
What does this mean? Weight cycling can lead to metabolic abnormalities and increase one’s risk of having diabetes.
6. It elevates the blood pressure levels
Yo-yo dieting can disrupt the blood pressure levels in the body.
Consumption of less food can lower the levels of potassium, sodium and other salts which can decrease the blood pressure.
On the other hand, fat deposition and increase of fatty tissues in the body as a result of yo-yo diet can lead to abnormalities in the metabolic profile and increased blood pressure or hypertension.
In animal models, it was discovered that increase and decrease of body weight at regular intervals caused the blood pressure levels and body fat to increase.
European Journal of Clinical Nutrition reports a study on women who had undergone weight cycling. The women having larger waist-to-hip ratio had increased chances of having high blood pressure.
In another study conducted on more than 3 thousand individuals, it was found that regular fluctuations in weight that may be caused by dieting can raise the blood pressure levels and increase the risk of metabolic syndrome.
What does this mean? Yo-yo diet can result in blood pressure discrepancies and cause blood pressure to lower and elevate.
7. It increases the chances of having heart diseases
The side effect of weight cycling includes hypertension, fat accumulation in the body, insulin resistance and disrupted lipid and glucose profiles, all of which increase the risk of cardiovascular ailments.
The yo-yo dieting with regular increase and decrease in weight leads to changes in the normal functioning and metabolic status of the body and causes internal fat deposition. This affects health adversely and can result in cardiovascular diseases.
In women, this type of dieting was associated with lower levels of HDL (High-Density Lipoprotein) cholesterol which is considered good for health.
The concentrations of this cholesterol are lowered to such an extent which increases one’s risk of cardiac abnormalities.
In studies in women, it has been associated with increased chances of having Myocardial infarction and stroke, along with other diseases like cancer, diabetes, and fractures.
In other studies conducted on over 10,000 men, it was found that fluctuations in weight led to higher occurrences of cardiovascular diseases and can cause mortality in men who are already at risk of developing these ailments due to other factors.
What does this mean? As yo-yo diet increases blood pressure, cholesterol levels and causes metabolic syndrome, it also increases the risk of having heart ailments like stroke and myocardial infarction.
8. It has psychological effects and disrupts mental health and well-being
Vitamin B and vitamin C are required by the body for the production of neurotransmitters like dopamine and serotonin, which enhance one’s mood.
Insufficient nutrients by restricted food intake will reduce production of these chemicals and can cause depression, mood swings and irritability.
Irregular dieting pattern makes a person hungry more often and makes him feel low, anxious and tired all the time.
Lethargy, irritability and poor concentration follow.
Also, as the effects are short-lived, after stopping the diet, the person gains weight again in no amount of time which lowers their self-esteem and desire to maintain a healthy weight.
The person can revert to binge eating and develop eating disorders like Bulimia Nervosa( eating a large amount of food in short time) or can make a person eat far too less leading to the development of Anorexia Nervosa (fear of gaining weight).
Also, this rigid and extreme dieting is difficult to follow for a longer time, and thus the person thinks that he/she has failed. This causes emotional distress.
What does this mean? Yo-yo diet adversely affects the mental health leading to emotional distress, binge eating, and lower self-esteem.
Yo-yo diet may help in losing weight quickly, but it has adverse effects on health.
Very little food intake results in lower metabolism, weaker bones, loss of muscle mass, infertility, nutritional deficiencies, and psychological issues.
It increases blood pressure and the risk of having obesity, diabetes, high cholesterol levels, and cardiovascular disease.
Over an extended period, this type of diet results in more weight regains and high body fat storage, which becomes even harder to lose.
A weight loss regime should not only restrict the intake of food but should be based on a combination of balanced diet and exercise.