Why Diets Don’t Work

A slim and healthy body is the key not only to self-confidence, but also to high activity levels, productivity, and longevity. Dozens of diseases can be warded off with healthy weight loss. One stage in the fight against excess weight is dieting. Some help shed weight and improve health, others act radically and do not spare the internal organs. However, there may come a time when no diet seems to work.

Why don’t diets work?

Before we move on to the question of “why don’t diets work?”, let’s define what “Diet” essentially is and how it differs from rational nutrition. 

By diet, we can mean entirely different concepts. From a scientific perspective, it is a diet plan characterized by the exclusion of certain foods for a short period. It is used as a treatment, and after achieving the desired effect, the forbidden foods are reintroduced into the diet.

For example, in cases of acute poisoning or intestinal infections, a special therapeutic diet is prescribed, excluding protein, salt, dairy products (etc.). But what’s important is that it’s for a short time. Afterwards, these products are reintroduced into the diet. It’s impossible to go without a balance of proteins, fats, and carbohydrates for a long time.

Rational nutrition is a physiologically adequate and balanced diet for healthy individuals, taking into account their gender, age, type of work, climate conditions, and balanced in terms of proteins, fats, and carbohydrates.

In other words, our body expends energy in the process of its vital activity, uses protein to build new cells, glucose for brain function, and so on. Our task is to replenish what has been spent.

Based on this, nutritionists around the world have established the ratio of proteins, fats, and carbohydrates (PFC) and developed formulas for calculating daily energy consumption.

What should be done with excess body weight? Follow a diet or rational nutrition?

From a medical point of view, excess body weight is a condition that steadily leads to complications such as arterial hypertension, diabetes mellitus, atherosclerosis, etc.

Since excess weight does not appear on its own, but rather as a result of violating principles of rational nutrition, it is important to understand where the mistake occurred and return to balance. Therefore, a diet is necessary, but definitely personalized and based on principles of rational nutrition, as it needs to be applied long-term.

Currently, the medical community of dietitians has gathered sufficient data and conducted a large number of studies to assert that a rational diet with reduced daily caloric intake outperforms extreme diets (reducing daily caloric intake to 700 kcal, intermittent fasting) in the long run for weight loss. It is the safest approach.

It cannot be said that other diets don’t work. They also have their place, but reliable studies without conflicts of interest have not been conducted.

Clinical Recommendations 2020

According to the clinical guidelines for obesity treatment (revision 2020), fasting is not recommended due to a lack of data on its effectiveness and safety in long-term obesity treatment. It must be acknowledged that diets do not work in the case of obesity. But what does work?

According to the latest research conducted in 2020, the most effective diet is recognized as the low-calorie one, which involves a caloric deficit. If you wish to lose weight effectively and safely, you need to assess how many calories you spend and consume 500-700 kcal less. It is also necessary to consider age, initial weight, and gender. In this way, you can lose up to 1 kg per week. This is a long journey to your desired weight; however, it allows you to maintain the result for a long time and develop a diet system that will be natural for you. It is worth noting that the diet is effective for the first 6 months. Beyond that, the diet does not work. If you need to lose more kilograms, you will need to introduce additional restrictions.

Important points of the study:

1. Typically, nutritionists refer to a plateau stage as the ‘plateau period.’ As you can see, it is normal for it to occur and is justified from a physiological and physical perspective. Those trying to lose weight often wonder what to do if diets don’t help, become discouraged, can’t resist, and return to their old eating habits, slip up, or stop eating altogether. Of course, this is a challenging period, but you need to be patient and continue following the recommendations.
2. The next important point — ‘Most types of diets are equally effective if they adhere to the principle of limiting overall calorie intake. The main predictor of a diet’s success is systematic adherence to it.’ So, it is not necessary to follow the previously popular fractional five-meal plan; you can stick to a three-meal plan but with a calorie deficit.

An important aspect is increasing physical activity

Without exercise, diets don’t work or work incorrectly. Exercise makes the necessary adjustments:

1. Reduces visceral fat and increases muscle mass.
2. Mitigates the reduction in resting energy expenditure caused by weight loss (helps overcome that plateau).
3. Lowers blood pressure.
4. Increases glucose tolerance, insulin sensitivity.
5. Improves lipid profile, positively affects long-term weight maintenance.

Recommended intensity of physical activity:

1. Increasing the level of physical activity (mainly aerobic) to 150 minutes per week is recommended during the weight loss phase.
2. More intensive physical activities (from 200 to 300 minutes per week) may be recommended for long-term weight maintenance.

A combined lifestyle change (diet change in addition to physical exercise) leads to more significant weight loss compared to ‘monotherapy’ (diet or physical exercise).

Why else might a calorie deficit not work?

Let’s identify additional factors why diets might not work:

1. Incorrect calculation of consumed food.
2. Improper distribution of meals throughout the day (e.g., no breakfast, a meager lunch, and a heavy dinner).
3. Sleep issues — Late bedtime, lack of sleep, or on the contrary, staying in bed too long (the impact of sleep on weight gain can be elaborated but that’s a huge separate article)

Secondary nature of gaining weight is rare, about 5% of all cases. This includes hypothyroidism (disorder of the thyroid gland), overproduction of cortisol (stress hormone), hyperprolactinemia. How to lose weight if diets don’t help due to natural weight gain? — Ideally, undergo a check-up with

How do popular diets work?

Among hundreds of diets on the internet, some have stood out and gained significant popularity. Generally, these diets can be divided into several categories:

1. Extreme reduction of calorie intake.

The diet involves a drastic reduction in calories. The food consumed within a day should fall within the parameters: 800 kcal + 70-100 g of protein + up to 15 g of fats + 30-80 grams of carbohydrates. This type of nutrition ensures rapid weight loss. It literally burns fat due to a sharp lack of calories. However, this effect will not last long, with 25% of the lost weight being muscle. Nutrition with a drastic calorie restriction can be temporary and serve solely as a starting point for further development of a proper nutrition system.

2. Low-fat diet.

With this diet, fats may constitute only 15-30% of the total mass of consumed food. In practice, with a diet of 1400 kcal, this is up to 40 grams of fat per day. Such diets are considered more effective than simple calorie reduction. By controlling consumed fats, the person triggers the process of burning their own fat. As a result, not only does the weight more effectively decrease, but the effect of the lost kilograms also lasts longer.

3. Low-carb diets.

The low-carb diet works on the principle of fat reduction. For instance, diets of this type don’t work for the same reasons. Consuming a low amount of carbohydrates leads to effective weight loss, and combined with strength training, helps preserve muscle mass. What constitutes this ‘low amount’? Today, scientists cannot set a standard that satisfies different types of studies. On average, this figure is 40-60%. To be fair, it should be noted that studies have proven that carbohydrate and fat restrictions work metabolically the same way.

4. High-protein diets.

The protein diet is one of the most popular. It’s no wonder. It is tasty, varied, effective, and allows you to maintain muscles while predominantly burning fat. A high-protein diet involves consuming protein at a rate of 30-60%. This is twice the amount compared to normal nutrition.

5. Keto diet.

The keto diet involves a shift to eating where the body burns ketone bodies instead of glucose. It is more a lifestyle than a ‘diet.’ Today, this nutritional principle is popular among celebrities. It’s hard to say if diets work or not. In each case, a diet can produce individual results. That is why it is essential to approach the question of nutrition responsibly, as you would with treating any other organ.

Possible Consequences of Diets

Each diet works individually, but the underlying principle is the same — deficit. It doesn’t matter whether it’s a deficit of calories, carbohydrates, or fats. There is also a flip side to every diet — the body adapts to new conditions and slows down the weight loss process, resulting in no diet truly working. Additionally, with rapid weight loss, there is a high risk of regaining the lost pounds. Ultimately, it’s difficult to say if diets help. On one hand, it’s a quick way to lose weight, improve skin condition, etc. On the other hand, there’s a risk of harming health and regaining the lost pounds and more. That’s why balanced nutrition is considered the healthiest approach.

When does a diet fail to help with weight loss and you need to see a doctor?

In some cases, diets don’t work at all. This is related to a person’s hormonal background, thyroid diseases, and other illnesses, metabolism.

These issues should not be attempted to solve on your own. You are very unlikely to even make a small change in the situation, but you can cause irreparable harm to your health in just a few weeks.

If you want to lose a significant amount of weight, are aware of any illness, or are trying to lose weight but no diets work, visit a doctor’s office. An examination and professional personal assessment will help you and a nutritionist select the right dietary system.