The fat cells in your belly will not get bigger from bad sitting posture.
In order for the fat cells in your belly to increase in size and give you a bigger stomach, you would have to take in MORE calories than you are burning.
It’s that simple.
Bad posture including when sitting does not slow one’s metabolism—it does not stunt your ability to burn the food you eat.
Bad sitting posture does not cause fat to accumulate in the so-called fat cells – not the ones in your stomach and not the ones in your thighs, hips or elsewhere.
Now, improper sitting posture can cause low back pain or even a strain in a back muscle.
But the accumulation or addition of fat in the belly goes back to that simple formula:
Calories In vs. Calories Out
Multiple things influence this formula. For example, there are medications that are associated with weight gain.
There are medical conditions that can cause fat gain such as low thyroid.
There are conditions that cause hunger such as diabetes and hypoglycemia.
Some medications increase appetite, too.
All of these factors will cause fluctuations in body weight.
Excessive sitting is associated very strongly with obesity and even slight overweight. The more you sit, the less time you’re walking or exercising!
But sitting POSTURE has absolutely no effect on the rate at which your body burns fat, calories or food. It has NO effect on the size of the fat cells in your belly.
When I was a personal trainer I never told my clients, “You can lose weight by improving your posture when sitting.”
And I never told my clients, “Sit upright rather than slouch, and watch the fat melt away.”
If you sit upright your belly won’t fold in on itself as much, and this will create an instant illusion of a trimmer middle. We all know that!
However, improving your posture when sitting will not speed up your metabolism, though it may make you feel perkier — which can then motivate you to get up and about more often — even hop on that dusty treadmill and stick to an exercise regimen — which can result in a loss of some belly fat.