Sitting for long periods can contribute to weight gain, take daily walk at least 10000 steps
Enough sleep
Lack of sleep can disrupt your metabolism and increase your appetite, which can contribute to weight gain
Avoid late-night snacking
Eating late night disturb sleep and metabolism that leads to weight gain .Try to avoid an hour before bedtime
Limit alcohol consumption
Alcohol is high in calories and can contribute to weight gain, especially in the belly area. Limit your alcohol consumption to one drink per day or less.
Drink more Water
Drinking plenty of water can help to flush out toxins, reduce bloating, and improve digestion. It can also help to reduce your appetite and increase feelings of fullness.
Patience and Consistancy
Loss of belly fat without exercise is quite difficult but not impossible so be patient and consistent in following these tips.