Effects of Caloric Restriction and Exercise on Body Weight, Immune Function, and Intestinal Flora

Effects of Caloric Restriction and Exercise on Body Weight, Cardiometabolic Risk Markers, Immune Function, and Intestinal Flora in College Students: a Randomized Controlled Trial

The purpose of this study is to estimate the effects of caloric restriction and exercise on body weight, cardiovascular metabolic markers, immune function, and intestinal flora among college students, as well as the underlying mechanisms.

In recent decades, carbohydrate-centered food pattern has brought worrying negative effects on human health, including increasing incidence of overweight, obesity, and cardiovascular diseases. Animal experiments based on rhesus monkey showed that caloric restriction could prolong their healthy life years, while reports from population-based studies are quite inconclusive. There are some studies reporting that caloric restriction did reduce the risk of cardiovascular disease in those with obesity, while some other cohort studies found that not eating breakfast might increase the risk of coronary heart disease, diabetes and other related diseases. In addition, a number of studies claimed that continuous caloric restriction is associated with the depletion of peripheral immune cells, immune suppression and reduced bone mineral density. In spite of those inconclusive results, on the whole, fasting and caloric restriction in some way do improve the conditions of metabolism, overweight and obesity. Previous studies mostly focused on middle-aged and elderly people, while recent studies in mice show that energy limitation in elderly people could not stop the aging process genetically or metabolically. Therefore, this study aims to estimate the effects of caloric restriction and exercise on body weight, cardiovascular metabolic markers, immune function, and intestinal flora among college students, as well as the underlying mechanisms. A pilot study containing around 40 participants will be conducted firstly to assess the feasibility of this intervention plan.

Participants would be required to take part in an exercise plan, under the instruction and guidance of professional sports teachers.

Rope-skipping exercise for three times a week (90 minutes each time, and there is a 10 min break after 20 min Rope skipping). Exercise bracelet and smart bracelet would be used to record the energy consumption throughout the study.

In the first two weeks, participants would reduce their daily energy intake to 100% -110% of his or her basal metabolic energy under instruction, and stick to it till the end of the intervention. According to the dietary recommendation proposed by Chinese government, participants are required to take in cereals, vegetables, fruits, meat and eggs, while minimize the consumption of sugar-sweeten beverages. Participants are instructed to arrange their three meals according to the recommended energy distribution (3:4:3).

Baseline (1-2 days before the intervention), right after intervention (8 weeks), 8 weeks after completion of the intervention

Baseline (1-2 days before the intervention), right after intervention (8 weeks), 8 weeks after completion of the intervention

Serum lipid levels (total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides) were analyzed by the enzymatic method.

Baseline (1-2 days before the intervention), right after intervention (8 weeks), 8 weeks after completion of the intervention

Baseline (1-2 days before the intervention), right after intervention (8 weeks), 8 weeks after completion of the intervention

Sitting systolic and diastolic blood pressure were measured with a validated mercury sphygmomanometer (model XJ1ID, China) and TZ-1 stethoscope.

Baseline (1-2 days before the intervention), right after intervention (8 weeks), 8 weeks after completion of the intervention

Immune and inflammatory indicators (ICAM-1, CCL2, VCAM-1, IL-6, IL-8, TNF-alpha, Leptin, Tau, BDNF, VEGF) were analyzed using the Luminex Human Magnetic Assay kit.

Baseline (1-2 days before the intervention), right after intervention (8 weeks), 8 weeks after completion of the intervention

Baseline (1-2 days before the intervention), right after intervention (8 weeks), 8 weeks after completion of the intervention

The executive functions were measured by the Behavior Rating Inventory of Executive Function-Adult Version (BRIEF-A) Self-Report Form. Items are rated 1 (never), 2 (sometimes), and 3 (often). There is no range for a total score. Raw scale scores are used to generate T-scores. A reduction in score indicates less impairment.

Baseline (1-2 days before the intervention), right after intervention (8 weeks), 8 weeks after completion of the intervention

Baseline (1-2 days before the intervention), right after intervention (8 weeks), 8 weeks after completion of the intervention

Inclusion Criteria: First and second year undergraduate students in Sun Yat-sen University. BMI≥22 kg/m2. Having the time and volunteering to receive the interventions. Exclusion Criteria: Currently engaged in other weight-lossing studies. With secondary obesity induced by medicine or other diseases. With high blood pressure, diabetes or other cadiovascular diseases. Contraindication to exercise.

Department of Maternal and Child Health and Sun Yat-sen Global Health Institute, School of Public Health and Institute of State Governance, Sun Yat-sen University