Diet Break - Is It Beneficial to Take a Hiatus From Calorie Reduction?

A calorie deficit diet is intended for people who want to lose excess weight and reduce body fat. Changing the way of eating is extremely important for health and allows to reduce the risk of many diseases. During the process of reducing body weight, it is important to take into account a calorie deficit (a so-called negative calorie balance is created). In the context of a calorie deficit diet, it is necessary to know a few concepts: PPM, CPM, and calorie deficit. PPM is the basic value of metabolism, the daily energy requirement that must be provided to the body to ensure its proper functioning under the conditions of physical and mental activity. This is the energy required for the functioning of the circulatory system, respiratory system, nervous system, sex organs, muscles, skin, and maintaining the correct body temperature. CPM, on the other hand, is the total value of metabolism, the daily energy requirement of the body, taking into account PPM and physical activity. Physical activity includes all activities performed during the day with low or moderate intensity, such as cleaning, washing, vacuuming, but also activities with higher intensity such as strength training, running, swimming, cycling. In addition, CPM also takes into account a certain amount of energy required for digesting food after consumption. A negative energy balance affects the reduction of body weight, a positive one on the increase, and a zero on maintaining it. A negative energy balance means that the energy taken in from food is less than the energy expended by the body. The calorie deficit should correspond to 10-15% of CPM and usually ranges from 200-500 kcal. The caloric intake in a calorie deficit diet should be between the values of CPM and PPM or individually adjusted to physical activity.

After a certain period of maintaining a calorie deficit, there may be a crisis characterized by fatigue, a feeling of hunger, and exhaustion due to adherence to dietary guidelines. This is the normal response of the body to maintaining an energy balance. This process involves hormones such as ghrelin, leptin, insulin, or testosterone. In such a crisis situation, a diet break, also known as a 'nutrition break', which lasts for about two weeks, can be helpful. During this time, a zero-energy balance should be maintained, which means supplying the body with the same number of calories as the CPM to maintain body weight. A study suggests that a diet break that corresponds to the CPM content reduces only a few calories and maintains body weight. This break not only restores strength and improves well-being, but also has a positive impact on thyroid function, sleep, mental well-being, concentration, and irritability. A study conducted on athletes and published by J. J. Peos and colleagues in 2021 found that a weekly diet break improved the performance of leg muscles but had no effect on the performance of arm muscles. Furthermore, the diet break increases lean body mass and resting metabolic rate, but has no significant impact on the level of fat tissue. Increasing calorie intake for a week reduces the feeling of hunger and leads to a weight gain of only about 0.6 kg. It is worth noting that hunger often leads to a deterioration in well-being and poorer athletic performance, while better concentration and less irritability contribute to better results. Studies suggest (J. J. Peos and colleagues 2019) that regular diet breaks are a more effective method of reducing fat tissue in non-exercising individuals (compared to a standard diet with a constant calorie deficit) and prevent rapid weight gain (the yo-yo effect). Diet breaks can also have a positive impact on the results of blood tests. S. H. Davoodi and colleagues found that in individuals who applied a diet with consideration of a break (11 days of a low-calorie diet and 4 days of a high-calorie diet), compared to those who constantly adhered to a reduced diet, there was a greater decrease in glucose, total cholesterol, and triglyceride levels. Furthermore, weight loss was more sustainable in those who took a diet break, and the participants were more satisfied. N. M. Byrne and colleagues showed in a study on a group of overweight men that those who adhered to a reduced diet with consideration of a diet break lost more kilograms and more fat tissue with preservation of lean body mass compared to participants who maintained a constant negative energy balance. Moreover, they maintained their body weight better after the end of the diet – this could be an effective method of preventing the yo-yo effect.

A persistent meal is a meal in which you can include something high in calories. A persistent day, on the other hand, is when you can afford to consume calorie-dense products throughout the day. This cannot be compared to a diet break because the time spent on a persistent meal or a persistent day (a few hours or one day) is shorter – in a study by S. H. Davoodi et al. Diet break lasts 4 days. It should be emphasized that there were no more or less caloric foods. However, it does not depend on specific foods, but on the excess calories supplied from both healthy and unhealthy sources. The use of a diet break has a positive impact on the physical and mental state of the body and can prevent the occurrence of the yo-yo effect. However, it is important to remember that a permanent change in dietary habits is crucial.