Diets: the yo-yo effect and its consequences for your heart health

What is the yo-yo effect?

When you drastically reduce the number of calories you consume, your body is forced to reduce its needs, and use less energy at rest. In order for the body to draw on its reserves (and therefore lose weight), it needs to burn more calories than it takes in. But as the metabolism adapts to be able to continue functioning at a lower calorie intake, the weight stabilises. And when you go back to eating as you did before, you take in more calories than you burn and your initial weight comes back: this is called the yo-yo effect.

A strong yo-yo effect is usually the result of a radical diet in which too few calories are consumed during a given period. When daily calorie intake is drastically reduced, the yo-yo effect is inevitable and you experience rapid weight gain after dieting.

What are the consequences of the yo-yo effect on your heart health?

Excessive weight fluctuations increase the risk of developing type 2 diabetes, as well as heart and kidney disease, according to a new study by researchers at Georgetown University in Washington, presented at the annual meeting of the American Physiological Society.

The scientists conducted an experiment on rats. The experiment showed that repeated weight loss and weight gain worsened their heart and kidney functions.

To achieve their results, the researchers divided the 16 rats they observed into two groups. One group was fed a normal amount of food throughout the experiment, while the other group was given a restrictive diet in three cycles, equivalent to 60% of their normal daily food intake, followed by a normal diet for three weeks. During the restrictive diet period, the rats lost 20% of their body weight. However, their weight eventually returned to normal.

At the end of the experiment, the researchers used ultrasound to assess heart and kidney function and blood tests to assess insulin sensitivity.

Results: weight loss and subsequent weight gain worsened the heart and kidney functions of the rodents.

Alina da Souza, lead author of the study, explains that the animals that lost and then gained weight were found to have poor heart and kidney functions at the end of the experiment. They also had more insulin resistance (2.6 times higher than in the control group) leading to high blood sugar levels, a precursor to type 2 diabetes. Despite the fact that the animals appear to be healthy after recovering from their diet, their heart isn't and their metabolism has changed.

The scientists now want to continue their research to better understand the long-term effects of dieting, especially when weight loss is rapid.

How to avoid the yo-yo effect?

The yo-yo effect is a real problem when it comes to losing weight. However, it is possible to avoid it, but you will have to use a different approach to weight loss.

Avoid extreme diets

Extreme diets are those where calorie restriction is drastic. Often, it is advised to consume only 1,000 calories per day, instead of 2,000 for women and 2,500 for men.

Of course you lose weight, but not because you have lost fat. First of all, you lose a lot of water. Then, the body does not compensate for the lack of energy by using body fat, instead, it relies on muscle mass. The cells are therefore destroyed one by one, and as a result you feel weak and lack energy.

Do not eat less, eat better

Very often it is recommended to eat less to lose weight, but it should be done with caution. If you are overweight, it is natural for you to have to eat less in order to lose weight. But that's not all: eating well is actually much more important.

Here is what you can do to eat better:

Avoid sugar: we consume large amounts of sugar, which is dangerous for our health. You should pay attention to the so-called "natural" sugars, namely those found in fruit and honey. These are natural sugars, often presented as "diet-friendly". Of course, fruit and honey contain nutrients and fibre, but the excess of sugar, whether refined or not, is not good for your health, as the body does not distinguish between the two. Eating fruit is good, but don't overdo it.

Replace fast carbohydrates with slow carbohydrates: all carbohydrates we eat are converted into glucose. Fast carbs are quickly absorbed by the body and converted into glucose. This leads to high blood sugar and, in turn, high insulin. However, energy bursts are short-lived and the extra energy is stored as fat for later use. It is therefore best to eat slow carbohydrates. These carbohydrates are slowly absorbed by the body and do not cause blood sugar levels to rise quickly, so there is no increase in insulin. Their energy is released in an optimal way, ensuring a long-lasting feeling of fullness. Slow carbohydrates are mainly found in wholegrain products (wholemeal pasta, wholemeal bread, brown rice, etc.).

Avoid bad fats: the body needs both good and bad fats, but we tend to eat too much bad fat at the expense of good fat. Bad fat is found in fried foods and many industrial products. Given their ubiquity in our diet, it is impossible to avoid them completely, nor is it really necessary. However, avoid them as much as possible. What you should consume is good fats, which you can find in nuts and oily fish (mackerel, herring, salmon, etc.).

Limit your calorie intake

The key is to limit your calorie intake so that your body won't think it is starving, and won't start storing fat and saving energy in anticipation of long-term hunger.

Watch your weight loss and make sure it is not too rapid. You may need to adjust your calorie intake later, based on how quickly you will be losing weight.

Exercise more

First of all, good nutrition is the most important factor in losing weight. Good nutrition is about 70% of the work. That leaves 30% for physical activity and sport. If you want to get the most out of your healthy diet, it is recommended that you exercise more. Doing sport is even better!

Slowly but surely

Losing weight slowly means getting the result that will last, so losing a little more than 2 pounds per week is a realistic goal. Don't forget to indulge yourself from time to time.

If you are on a diet, weigh yourself regularly to make sure you are losing weight. The most important thing is to avoid sudden weight loss. If you lose weight too quickly, you need to adjust your diet so that your metabolism does not slow down.