# Effects of Long-Term Calorie Restriction and Physical Activity on Body Weight and Metabolism Applied to Different Degrees of Obesity

## TL;DR

This study shows that calorie restriction and physical activity reduce body weight and improve insulin levels in obese individuals, with some metabolic changes varying by weight loss amount.

## Contribution

The study demonstrates that lifestyle interventions consistently improve insulin resistance across varying obesity levels.

## Key findings

- Obese individuals lost an average of 8.6% of their weight after 12 weeks of calorie restriction and physical activity.
- Insulin levels decreased significantly in all obese groups post-intervention.
- Weight loss of more than 10% led to a significant decrease in insulin levels but not other metabolic markers.

## Abstract

The aim of the study is to investigate whether long-term calorie restriction and physical activity have an effect on body weight and metabolism in obese individuals with different body mass indexes (BMIs).

Fifty-four obese women who were not receiving any obesity treatment were included in the study. Participants received 12 weeks of low-calorie diet and physical activity training appropriate to their age, gender, and BMI. Body weights were measured at the initial visit and after the intervention. Venous blood samples were collected twice: before and after the intervention. Baseline glucose, insulin, total cholesterol (TC), triglyceride (TG), HbA1c, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) levels were measured using a Beckman Coulter AU 5800 clinical chemistry autoanalyzer. Hemoglobin A1c (HbA1c) levels were determined using boronate affinity and HPLC techniques using a Tirinity Biotech Premier 9210 autoanalyzer.Homeostatic model assessment of insulin resistance (HOMA-IR) was calculated using the formula (fasting insulin [μU/mL] × fasting glucose [mg/dL])/405).

In the study, insulin and HOMA-IR levels increased significantly as the degree of obesity increased (P < .05). Obese individuals lost an average of 8.6% weight after the combined treatment, and when repeated measurement results were compared, insulin levels in all obese groups decreased significantly (P < .05). HbA1c levels decreased significantly only in moderately obese individuals after the treatment (P < .05). In the first group (those who lost between 5% and 9.9% of their weight), TG and insulin levels decreased while TC, LDL-C, and glucose levels increased (P < .05). In the second group (those who lost more than 10% of their weight), only insulin levels decreased (P < .05).

As obesity increased HOMA-IR levels an indicator of insulin resistance increased significantly. Participants lost an average of 8.6% of their weight and insulin levels decreased significantly after the intervention. Long-term lifestyle interventions produced relatively similar effects on metabolism across different obesity levels.