It's important to tell your doctor if you have other symptoms besides difficulty controlling your weight. Your weight problem may be part of another medical condition. 
Tell your doctor if you feel:
Short of breath.
If you're a woman, tell your doctor if:Cushing's syndrome
A condition called Cushing's syndrome can make you gain weight, especially on your face and around your waist. It means your body is making too many corticosteroids. These are chemicals that control how your body uses fat and sugar. If you have too many corticosteroids, you can feel tired, hungry, and bloated.
It may happen when a lump grows in your adrenal glands. These glands lie on the surface of your kidney. Your adrenal glands make corticosteroids. The lump makes your body produce extra corticosteroids. Cushing's syndrome can also happen when lumps grow on your pituitary gland or another part of your body. Hypothyroidism
This means that your thyroid gland is not working properly. Your thyroid gland is a small gland at the front of your neck. It makes a chemical that helps to control how much energy your body uses (it changes your metabolic rate).
If you have hypothyroidism, your thyroid gland doesn't make enough of this chemical. This means that your metabolic rate slows down. So you burn fewer calories, and you're more likely to put on weight.
To read more, see our information on Underactive thyroid. Polycystic ovary syndrome
Only women can get this condition. It's often called PCOS for short. It means that small cysts (little bags of fluid, like blisters) may grow in the ovaries. Women who have PCOS don't release eggs regularly (ovulate). It happens because of an upset in the balance of certain hormones.
About half the women with PCOS are obese. But we don't know which comes first, the condition or the obesity. If your periods stop or become irregular and you put on weight at the same time, it's important to tell your doctor. Lots of unwanted hair on your body or face can also be a sign of polycystic ovary syndrome.Insulinoma
This condition is caused by a lump (tumour) in your pancreas. The tumour makes your pancreas produce extra insulin, a chemical your body uses to control the amount of sugar in your blood.
The extra insulin changes sugar into fat. And you may not have enough sugar left in your blood. So your brain tells you that you feel hungry and you may eat more. Brain tumour
If a tumour grows in the parts of your brain that control appetite and the amount of energy your body uses, your brain won't do its job very well. So you may put on weight. But it's unlikely that putting on weight would be the only symptom, if you had a brain tumour.