To lose weight, it’s important to make lifestyle changes with a focus on reducing calories from food and beverages, a healthy eating plan, and portion control. Follow a healthy diet, and if you are overweight, reduce your daily intake by 500-1000 calories for weight loss of 1-2 pound
The same amount of energy IN and energy OUT over time = weight stays the same
More energy IN than OUT over time = weight gain
More energy OUT than IN over time = weight loss
You may refer https://www.nhlbi.nih.gov/health/educational/lose_wt/eat/menus.htm for more information