Why fewer calories and more exercise will not necessarily lead to weight loss.





Why is it so difficult to maintain a healthy weight after a diet? - An extensive survey to understand the perceptions, attitudes, and obstacles in the treatment of obesity, conducted in 11 countries, confirmed what most of us already knew: it’s difficult to maintain long-term dietary gains. Only about 11 percent of people living with obesity were able, according to the survey, to maintain a five percent weight reduction for a period of at least one year.

There are several reasons for this. First and foremost, the difficulty in sustaining weight loss is related to the fact that obesity is a chronic disease. If we try to summarise in simple words "what is obesity"? Simply, it is about storing the excess calories in the body in adipose (fat) tissue, or muscle.

The genetic load, along with other biological processes, dictates at what rate the calories will be stored, how they will be used for daily energy expenditure, and in which tissue the excess calories will be stored. When excess calories accumulate in adipose tissue and lead to saturation, there is a rapid and abnormal proliferation of fat in tissues where it is not supposed to accumulate, such as in the liver, pancreas, heart muscle, kidneys and even the brain. Fat interferes with the function of these organs, and along with difficulty in transporting blood, inflammatory processes are formed in these organs.

Consequences may include the development of diabetes, due to difficulty in secreting insulin from the saturated pancreas, along with difficulties in the proper functioning of insulin in target organs, such as muscle and liver, or the formation of cardiovascular disease: Myocardium (heart muscle) functions reduced and leads to insufficiency, as blood vessels develop Sclerosis, due to fat proliferation and inflammatory processes in the walls of the blood vessels.

Metabolically, obesity accelerates the development of diseases such as type 2 diabetes and cardiovascular disease. It burdens body organs, including skeletal muscles and bones, and produces pressure from the increased adipose tissue on the airways (pressure that can lead to sleep apnea) or pressure on the kidneys, which can lead to hypertension (high blood pressure).

Further, in terms of malignancies, obesity is a risk factor. A substantial connection was found between obesity and the development of tumor processes such as breast cancer. At the times of Covid19, the connection between corona complications and obesity has also become clear.

In addition to the many physiological aspects, obesity also has a bad mental effect. The rates of depression and mental disorders are higher among obese people.


“If you eat less and exercise more – you’ll lose weight” - Another reason why it is difficult to maintain weight loss, is related to the misconception, according to which: if we eat less and do more exercise - we lose weight. That is not necessarily true. It is now clear to us, health professionals, that there is no direct and constant line drawn between obesity and gluttony and laziness, it is the physiological changes that lead to the behavioral changes.


Recurrent weight gain begins after six months to a year from the weight loss process. It also leads to an increase in the percentage of body fat compared to its rate at the time of starting the diet

Many studies show that re-weight gain begins six months to a year after the weight loss process. It also leads to an increase in the percentage of body fat compared to its volume at the beginning of the diet, and involves two powerful physiological processes:

The first is related to the hunger mechanism: studies in subjects who had undergone low-calorie diets demonstrated two parallel effects. On the one hand, an increase in hunger hormone levels (called: ghrelin), even a year after stopping the diet and on the other hand, a decrease in satiety hormones (called: GLP-1 and PYY). The result is a decrease in the feeling of satiety and an increase in the feeling of hunger - effects that encourage increased food consumption.

The second process is related to a decrease in energy expenditure: after weight loss, the body becomes more efficient in conserving energy, and reduces the "wastage" of daily energy by an average of 300 calories, in a process called "metabolic adaptation". Various studies further show that routine exercise has little contribution to weight reduction.

The explanation for this has to do with our survival mechanisms, which protect the body from the reduction of adipose tissue, which serves as the energy reserve storage. Decreased adipose tissue level signals to the brain control mechanisms that there is a potential survival threat.

After weight loss, the body becomes more efficient at conserving energy, reducing the "waste" of daily energy by an average of 300 calories per day, in a process called "metabolic adaptation."

But why is it at all necessary to protect excess body weight? To understand this, we must familiarize ourselves with the phrase "balance point." This refers to the threshold point at which the body mechanisms perceive body weight as being normal. Various factors in our lives may raise this threshold, including:

  • Consumption of unhealthy food contents, such as: processed foods high in simple carbohydrates, sodium and fat.

  • Poor sleep, which manifests itself as a result of lack in hour of sleep and extensive use of screens, which reduce the level of the hormone melatonin in the body (which encourages healthy sleep).

  • Feelings of stress, which raise the levels of cortisol, a hormone that reduces the rate of metabolism in the body which leads to obesity.

  • A decrease in physical activity, resulting in a reduction in mediators that are released from the muscles, increase the feeling of satiety and improve our metabolic health (such as reducing blood sugar).

  • Use of various medications, whose side effects cause weight gain.

In light of all this, adhering to the maxim: "Reducing food consumption and increasing physical activity - ensures weight loss" - is a mistake and it also contributes to the creation of a negative image of people who are living with obesity.


So, what is the solution for sustaining dietary gains and maintain a healthy weight? – First, understand that obesity is a chronic and recurrent disease that is rooted in abnormal physiological processes, requiring long-term treatment - sometimes for life. Second, it should be understood that obesity is not a single disease. There is great variability between obesity processes and responses to different therapies. Unfortunately, medical science does not yet have good enough tools to predict what type of obesity a particular person has and what the most accurate treatment is for him or her. We live in an age of trial and error. Take a particular dietary approach, and if it fails, switch to another approach, based on a number of guiding principles:

  • Outlining a therapeutic approach that the patient can maintain for the rest of his life. The "once and it’s done" method is ineffective and leads to dangerous weight fluctuations.

  • Reducing the threshold of the balance point by addressing the factors that raise it: