A tummy tuck addresses three problems at once, which is why it succeeds where diet and exercise stall.
It repairs separated muscles. During pregnancy or weight gain, the two bands of abdominal muscle down the center of your stomach can stretch apart, a condition called diastasis recti. Once separated, they no longer hold the abdomen flat, which leaves a bulge that crunches and planks cannot fix because the muscles themselves are no longer together. A tummy tuck stitches them back into place, rebuilding the core from the inside.
It removes excess skin. After pregnancy or major weight loss, the skin of the abdomen is often stretched beyond what it can shrink back to. A tummy tuck removes that loose, hanging skin, including the area below the belly button where stretch marks and laxity tend to collect.
It removes stubborn fat. Localized fat is treated at the same time, often with liposuction, to smooth and refine the contour.
The combination is what gives a tummy tuck its dramatic, lasting result.