The reasons that can be primarily attributed to weight gain are unhealthy eating habits and lack of fitness exercises. Well, definitely it cannot be denied that these are indeed the major factors that make you overweight, but another fact is that there are also some other reasons for rapid weight gain. And it is this unexplained rapid weight gain that paves way for the entry of frustration, thereby, disturbing your peace of mind.

Here are a couple of causes of rapid weight gain:
 

Hypothyroidism: basically it is a thyroid hormone deficiency that affects the very metabolism of food, thus leading to weight gain. It is characterized by symptoms like fatigue, coarse skin, swelling of the face, intolerance to cold and headache.
 

Essential Fatty Acid Deficiency: the body needs essential fatty acids to make hormones, as they help to maintain the body's metabolism system. It is the deficiency of these essential fatty acids in the body that leads to food cravings and that too especially for fatty foodstuff. Some of its symptoms include dandruff, dry hair, arthritis problem, diabetes etc.
 

Food Sensitivity: some people are sensitive towards particular foods and if by chance or owing to ignorance, if they happen to consume such food items, then it is likely that it might lead to fluid retention, thus increasing their weight. Some of the early signs of food sensitivity are headache, fatigue, depression, pain in joints, sinus problem etc.

There are some prescription drugs like steroids, no steroidal anti-inflammatory drugs (NSAIDs), antidepressants and diabetic medications that tend to cause weight gain. Emotional eating is one another common reason for weight gain and it takes place as a result of responding to stress or depression.