Processed food

Calorie-dense processed foods are one of the prime culprits for weight gain in women. Processed foods contain a lot more calories per serving than unprocessed foods and can easily add extra pounds. You may be eating small amounts of such food; the calories will still be on the higher side. The added calories do not satisfy the hunger.
Menopause

Menopause is yet another cause for weight gain in women. It increases the appetite, leading to weight gain. Although, it may be hard to avoid such weight gain as it depends on the composition of the body, the overall weight gain would not be too much.
Poor Eating Habits

It has been observed that women are more inclined towards dieting rather than following a healthy diet plan. Dieting, i.e. continuously eating less than enough, leads to slow down in the metabolism and the body begins to store fat. The tendency to lose weight, on the contrary, makes women gain weight.
Pregnancy

One of the unavoidable as well as welcomed causes of weight gain in women is pregnancy. Since they are supposed to be eating some extra calories it is normal to gain some weight, however, many women consume too many calories when they are expecting. It is recommended that a healthy woman with an average body weight should eat only an extra 300 calories during pregnancy.
Emotional Eating

Many women tend to eat more during depression. Chocolate, sweets, and other comfort foods help them fill a void in life. The benefits, however, are usually short lived, but the extra pounds gained due to such emotional eating stay for long.
Low-Fat Foods

Women conscious about figure, usually get attracted to food with labels that read "low-fat", however, these low-fat foods often contain as many calories as other food items. The buyer enjoys feeding on such foods without realizing the high amount of calorie that is still going in.
Birth Control

Birth control pills have a known side effect of gain in weight. Women usually gain weight when they start taking contraceptive pills.
Lack of Sleep

When someone does not get ample amount of sleep the body reacts by storing fat. Women are getting more deprived of sleep due to work, depression and busy schedules. Without sleep, the body is unable to work normally and tries to overcome it by storing fat.
Low fiber diet

Lack of fiber can also be accounted for weight gain in women. Fiber not only promotes bowel health, it also gives you a feeling of fullness which makes you to eat less, thus avoiding possible weight gain. Fiber is essential in losing and maintaining a healthy weight.
Stress

Stress causes the body to enter defensive mode. Preparing for worse, the body begins to slow down and store fat. Stress is one of the most common factors for weight gain in women.