No Significant Effect of the Individual Chronotype on the Result of Moderate Calorie Restriction for Obesity—A Pilot Study

Background: Chronotype is the pattern of the circadian rhythm that allows an individual to optimize times of sleep and activity. It has been observed that chronotypes may associate with some conditions and diseases, including obesity. It is not known, however, whether chronotypes determine the effectiveness of weight loss regimens. Therefore, in the present study, we compared the outcomes of a 3-week moderate calorie restriction undertaken by individuals with obesity under the same controlled hospital conditions. Methods: A total of 131 participants with obesity (median BMI 40.0) were studied. The subjects underwent the same dietary intervention over 3 weeks, with a 30% reduction in daily caloric intake. The individual chronotypes were assessed by the morning and evening questionnaire (MEQ) according to Horne and Östberg. Anthropometric and biochemical parameters were assessed by routine methods. Results: Of all patients examined, 75% had the morning (lark) chronotype and 25% had the evening (owl) chronotype. These patient sub-groups did not differ in terms of demographic, anthropometric and biochemical characteristics at baseline. After 3 weeks of calorie restriction, both groups experienced a similar loss of weight and BMI (Body Mass Index) (3.4 ± 0.38% for larks vs. 4.1 ± 0.47% for owls, p = 0.45), with owls exhibiting a marginally greater loss of body fat (3.1 ± 0.79%) compared with larks (2.6 ± 0.64%), p = 0.02. On the other hand, the larks had a more discernable, but not statistically significant from owls, decrease in glycated haemoglobin and CRP (C Reactive Protein). Conclusions: The chronotype of individuals with obesity does not have a significant effect on the magnitude of the body weight loss, but there is a tendency observed towards the reduction in body fat content in owls through changing their meal and sleep timing to earlier hours, in response to moderate calorie restriction applied under the same controlled conditions

Iryzyna w świetle najnowszego piśmiennictwa

Irisin is an adipomyokine, which promotes the increase of non-shivering thermogenesis andwhich levels are affected by physical activity. Numerous studies have shown its relationshipto the body’s energy balance, the occurrence of insulin resistance, and components of metabolicsyndrome. It was noted that the serum concentration of irisin is significantly higher inobese subjects. Furthermore, irisin resistance has also been reported. It was discovered that,in response to reduced insulin sensitivity, an increase in the production of this adipomyokineoccurs. Irisin is involved in the regulation of carbohydrate metabolism. Multiple scientific havealso suggested the importance of diet in modulating the concentration of irisin. The DASH diet(Dietary Approaches to Stop Hypertension) and low glycemic index diet have been shown toexert the most beneficial impact on the ser um level of irisin. F urther studies are needed toexplore the role of low levels of irisin in the pathogenesis of type 2 diabetes.Iryzyna jest adipomiokiną, która sprzyja wzmożonej termogenezie bezdrżeniowej. Na jej sekrecję wpływa też aktywność fizyczna. Wyniki licznych badań wykazały związek iryzyny z równowagą energetyczną organizmu, zjawiskiem insulinooporności oraz składowymi zespołu metabolicznego. Zaobserwowano, że stężenie iryzyny w surowicy jest większe u osób otyłych. Wykazano również występowanie zjawiska oporności na iryzynę. Obserwuje się, że w odpowiedzi na obniżoną insulinowrażliwość następuje zwiększone wytwarzanie danej adipomiokiny. Iryzyna bierze udział w regulacji gospodarki węglowodanowej. Coraz więcej doniesień naukowych wskazuje na znaczenie sposobu żywienia w modulowaniu jej stężenia. Wykazano, że dieta DASH  oraz dieta o niskim indeksie glikemicznym, najkorzystniej wpływają na stężenie iryzyny w surowicy. Konieczne są dalsze badania nad rolą niskiego stężenia iryzyny w patogenezie cukrzycy typu 2

No Significant Effect of the Individual Chronotype on the Result of Moderate Calorie Restriction for Obesity—A Pilot Study

Background: Chronotype is the pattern of the circadian rhythm that allows an individual to optimize times of sleep and activity. It has been observed that chronotypes may associate with some conditions and diseases, including obesity. It is not known, however, whether chronotypes determine the effectiveness of weight loss regimens. Therefore, in the present study, we compared the outcomes of a 3-week moderate calorie restriction undertaken by individuals with obesity under the same controlled hospital conditions. Methods: A total of 131 participants with obesity (median BMI 40.0) were studied. The subjects underwent the same dietary intervention over 3 weeks, with a 30% reduction in daily caloric intake. The individual chronotypes were assessed by the morning and evening questionnaire (MEQ) according to Horne and Östberg. Anthropometric and biochemical parameters were assessed by routine methods. Results: Of all patients examined, 75% had the morning (lark) chronotype and 25% had the evening (owl) chronotype. These patient sub-groups did not differ in terms of demographic, anthropometric and biochemical characteristics at baseline. After 3 weeks of calorie restriction, both groups experienced a similar loss of weight and BMI (Body Mass Index) (3.4 ± 0.38% for larks vs. 4.1 ± 0.47% for owls, p = 0.45), with owls exhibiting a marginally greater loss of body fat (3.1 ± 0.79%) compared with larks (2.6 ± 0.64%), p = 0.02. On the other hand, the larks had a more discernable, but not statistically significant from owls, decrease in glycated haemoglobin and CRP (C Reactive Protein). Conclusions: The chronotype of individuals with obesity does not have a significant effect on the magnitude of the body weight loss, but there is a tendency observed towards the reduction in body fat content in owls through changing their meal and sleep timing to earlier hours, in response to moderate calorie restriction applied under the same controlled conditions