Why Muscle Size and Health Vary with Diet in Young Adults

Young Japanese adults, both men and women, were studied to see how their daily diet links to the amount of muscle in their trunk and the presence of fat within those muscles. This study focused on people aged 20 to 26. To measure trunk muscle thickness (MT) and echo intensity (EI), which shows how much non-contractile tissue like fat is present, ultrasound was used at the 3rd lumbar vertebra. Besides this, the study checked other health factors. These included pulse wave velocity (baPWV) and blood properties like triglycerides, total cholesterol, and fasting glucose levels.The results showed that for young men, muscle thickness was linked to the percentage of energy from polyunsaturated fatty acids and carbohydrates. However, it was negatively associated with carbohydrates. On the other hand, higher fat content within their muscles was linked to a diet high in saturated fats. For young women, the fat content inside their muscles was related to their blood circulation quality, measured by baPWV. These findings hint that the impact of daily diet on trunk muscles varies between young men and women.