What the silhouette colors represent
A body-fat distribution heatmap maps where fat tends to accumulate on the body, shading regions from cool colors for areas that typically carry and lose fat readily to warm colors for depots that store fat more persistently. It is a visual summary of population tendencies, not a measurement of any one person.
Common patterns differ by sex and hormones: many men store abdominal and visceral fat more readily, while many women store more in the hips and thighs. Individual distribution still varies widely and is strongly influenced by genetics.
Why some regions are described as stubborn
Fat cells in different regions vary in their density of adrenergic receptors, which affects how readily stored fat is mobilized. Regions richer in receptors that resist fat release tend to shrink later during weight loss, which is the physiological basis for the popular notion of stubborn fat.
Where you lose fat first is largely outside conscious control; overall fat loss comes from sustained energy balance, not from targeting a region. This is general educational information, not medical or dietary advice.