While a few decades ago, in the era of diets and quick-weight-loss myths, weight loss was mostly about calorie restriction, we now have much more science-based facts that allow us to understand the processes that occur in the body. And these facts are changing our ideas about what really works and what doesn't.

The key to weight loss is a calorie deficit

The basic rule of weight loss is indeed a calorie deficit — you must consume less energy than you expend. This statement remains relevant. However, recent studies show that the quality of calories also matters. And it's not just about the amount of food you consume, but also its composition.

In 2018, a study was conducted and published in the journal Cell MetabolismIt showed that the bodies of people on low-calorie diets, even when they are in a calorie deficit, can store fat if the diet lacks enough nutrients. Deficiencies in proteins, vitamins and minerals significantly slow down metabolism and disrupt normal body functioning.

So, you can't just reduce calories and hope for results - it's important to provide the body with all the necessary nutrients..

Studies confirm that eating 80% determines weight loss success. One such study is a 2015 paper published in The Lancet Diabetes & Endocrinology, which showed that high-protein diets help reduce appetite, improve metabolism, and preserve muscle mass during a calorie deficit.

Another study conducted in 2016 in Journal of Nutrition, showed that consuming enough fiber also helps reduce appetite and improve digestive processes, which is an important aspect for healthy weight loss.

Additionally, consuming healthy fats, such as omega-3 fatty acids, can help reduce inflammation in the body, which helps the body normalize metabolism. Recent research published in American Journal of Clinical Nutrition in 2018, showed that omega-3s help reduce abdominal fat, which is one of the most harmful types of fat for health.

Metabolism and its impact on the weight loss process

Metabolism is not just the rate at which you burn calories, but also how your body uses and stores energy. Its complex mechanism involves many factors, from genetics to physical activity.

A study conducted in 2021 in Nature Reviews Endocrinology, has shown that muscle mass has a large impact on basal metabolic rate. People with more muscle mass burn more calories even at rest because muscle requires more energy to maintain its function.

This also highlights the importance of strength training in the weight loss process. The study, published in American Journal of Physiology, proves that strength training, even without significant aerobic exercise, can increase overall metabolic rate.

The role of exercise

Physical activity is critical to successful weight loss, and this has been confirmed by many studies. However, it is important to understand that not all types of exercise are created equal.

A 2018 study in Journal of Obesity showed that just 30 minutes of aerobic exercise, 5 times a week, can significantly increase energy levels and improve overall health, but to burn fat without losing muscle mass, it's important to combine cardio with strength training.

According to a study conducted in 2019 and published in Obesity Reviews, the best results for fat loss are achieved by combining cardio and strength training. Strength training, even if it doesn't lead to significant weight loss, can increase metabolism and preserve muscle mass, which is critical for sustainable weight loss.

Psychological track

Weight loss is not only a physiological process, but also a psychological one. Constant stress, misunderstandings about food, and incorrect attitudes can lead to the opposite effect.

A study published in Journal of Clinical Psychology in 2020, showed that people who have stable psychological support during weight loss achieve significantly better results. At the same time, those who experience stress or depression are more likely to overeat and regain weight after losing it.

According to other studies, regular relaxation exercises, such as yoga or meditation, can help reduce stress levels and cortisol, a hormone responsible for fat storage in the body.

Sleep to lose weight

Sleep is one of the main components of a healthy weight loss process. A recent study published in Current Biology in 2020, found that sleep deprivation significantly disrupts the balance of hormones that regulate appetite. In the short term, this can lead to increased levels of the hormone ghrelin, which stimulates hunger, and decreased levels of leptin, which controls feelings of fullness. As a result, people who sleep less than 7 hours a night are more likely to feel very hungry and are more likely to overeat, especially foods high in calories, sugar, and fat.

A study published in American Journal of Clinical Nutrition in 2016, showed that even one night of sleep deprivation can disrupt metabolic processes, reducing the body's ability to burn fat and increasing cravings for unhealthy foods. Ideally, a person should sleep 7-9 hours a day to maintain normal hormonal balance and maintain a healthy metabolism.

Life in balance 

This is perhaps the most important rule. Only by combining healthy sleep, physical activity, and effective stress management can you achieve real, sustainable weight loss results without resorting to extremes or excessive restrictions. 

It's important to remember that we're all different, and what works for one person may not work for another. However, with modern science, we can build healthy and effective strategies to achieve our goals.