What theory suggests that body fat and health risk increase linearly after reaching certain thresholds?

The theory that suggests body fat and health risk increase linearly after reaching certain thresholds is Linear Risk theory. This concept posits that as body fat increases beyond a specific point, the associated health risks rise in a direct, proportional manner. This linear relationship implies that there are identifiable thresholds of body fat where the risk for health issues, such as cardiovascular disease, type 2 diabetes, and other obesity-related complications, begins to escalate predictably.

In contrast, Body Mass Index theory and Body Fat Percentage theory do not specifically address the linear nature of health risks or the thresholds at which risks begin to climb. They focus more on categorizing individuals based on their weight-to-height ratio or the proportion of body fat relative to body composition, respectively. Health Threshold theory has merit in discussing the point at which health risks begin to increase, but it does not inherently imply a linear progression in risk as body fat rises, which is the distinctive characteristic of Linear Risk theory.