Only partially true. Think about this … it would take 250,000 sit-ups to lose 1lb off your waist-line !!
So there has got to be an easier way & there is.
There are 2 things you need to address to keep a firm tummy.
1—diet. Stay away from any foods that are creamy, contain flour of any kind & all dairy products.
If these are part of your regular diet you are just fighting a losing battle.
2 – exercise. Yes, sit-ups are a must but be sure that you do them properly & you know how to exercise the lower abdominals, upper abdominals & the side abdominals.
But even more important is the cardio.
Make sure you do it.
Bike riding &/or brisk walking will go a long way to firming up that tummy more than you know.
3 times per week for 45 to 60 min.
Not only will you look better but you will feel better mentally & physically.