Older adults who are more physically fit tend to have less body fat, especially fat around the organs, even if their weight looks normal.

Older adults who are more physically fit tend to have lower levels of 'bad' cholesterol in their blood.

In young, lean men, those with higher cardiovascular fitness before overeating tend to gain less fat and total body energy when consuming excess calories for 100 days, indicating that fitness level may affect how the body stores or uses extra calories.

The link between muscle mass or calorie burn and how much you eat gets weaker the older you get.

The amount of fat stored around internal organs and within muscles and the liver is more strongly linked to signs of aging in the heart and blood vessels than overall body weight measured by BMI.

In middle-aged adults, having more fat around the internal organs is linked to a faster rate of cardiovascular aging, with each additional liter of this fat corresponding to an extra 0.656 years of biological aging in the heart and blood vessels, even after accounting for overall body weight and chronological age.