Weight gain and loss are a result of the balance between calories consumed and calories burned. To gain weight, you eat more calories than you burn, and to lose weight, you burn more calories than you eat
Some factors that can affect weight include:
Diet
Processed foods are often designed to be tasty and addictive, which can lead to overeating.
Metabolism
A faster metabolism means you burn more calories at rest and during activity.
Sleep
Poor sleep can increase fat stores and stress hormone levels
Genes
More than 400 genes have been linked to weight gain, and some can make it harder to lose weight.
Exercise
Aerobic exercise strengthens the heart and increases healthy cholesterol levels. Isometric exercise, like strength training, works muscles and strengthens bones, which can increase metabolism and burn fat.