some mis-information in here, there are a few illnesses that can actually make one gain a ton of weight. One serious one is called Cushing's syndrome.
Cushing's Syndrome
Introduction
What are the symptoms?
Cushing's syndrome is a hormonal disorder caused by prolonged exposure of the body's tissues to high levels of the hormone cortisol. Sometimes called "hypercortisolism," it is relatively rare and most commonly affects adults aged 20 to 50. An estimated 10 to 15 of every million people are affected each year.
What are the symptoms?
Symptoms vary, but most people have upper body obesity, rounded face, increased fat around the neck, and thinning arms and legs. Children tend to be obese with slowed growth rates.
Other symptoms appear in the skin, which becomes fragile and thin. It bruises easily and heals poorly. Purplish pink stretch marks may appear on the abdomen, thighs, buttocks, arms and breasts. The bones are weakened, and routine activities such as bending, lifting or rising from a chair may lead to backaches, rib and spinal column fractures.
Most people have severe fatigue, weak muscles, high blood pressure and high blood sugar. Irritability, anxiety and depression are common.
Women usually have excess hair growth on their faces, necks, chests, abdomens, and thighs. Their menstrual periods may become irregular or stop. Men have decreased fertility with diminished or absent desire for sex.
What causes Cushing's syndrome?
Cushing's syndrome occurs when the body's tissues are exposed to excessive levels of cortisol for long periods of time. Many people suffer the symptoms of Cushing's syndrome because they take glucocorticoid hormones such as prednisone for asthma, rheumatoid arthritis, lupus and other inflammatory diseases, or for immunosuppression after transplantation
http://www.endocrine.niddk.nih.gov/pubs/cushings/cushings.htm
Your friend needs to have a blood work up to check her cortisol levels.