India, Sept. 23 -- Many people struggle with stubborn belly fat, even when they eat right and exercise regularly. Often, it's not just about diet or workouts. Fitness coach Lars Meidell, in his September 16 Instagram post, reveals the number one reason you're not losing belly fat and shares a 90-day plan to finally tackle it. (Also read: Fitness coach says 'walk like your life depends on it', shares 10 rules to melt belly fat and get lean by New Year )

"The #1 reason why you're not losing belly fat is not because of your age or busy schedule. It's actually your damaged metabolism," says Lars. He further explains how you can fix it in 90 days.

50 push-ups

50 body squats

50 lunges

50-sec wall sit

50-sec plank

-Terrible sleep schedule...