In Ayurveda Kapha is considered the most beautiful body type, with some strength and a bit of meat on their bones. In Western culture it is the lithe, wiry frame of Vata is considered most attractive. As a 52kg Vata, I'm telling you, this is not desirable for your health. A word of caution. Please approach weight loss with a Satvic (pure) mind, you truly know what your healthy weight is.
Obesity is predominantly Kapha. But if your weight gain/loss is irregular (Vata) or your appetite is very high (Pita) do not follow this advice. This diet will dry out the water in your body, by applying fire and air. Fire and air will raise Vata and Pita.
Having established you are Kapha imbalanced, the first thing is to reduce the minds attachment to food, no mean feat for loving Kapha. It is important not to diet too strongly or the mind will rebel. Be gentle, replace foods rather than giving them up entirely, and take things one step at a time. One advantage Kapha has here is endurance, use it.
Reduce your intake of sweet food, this includes most fruit, rice, wheat, meats and oils. Take less dairy products, salt, and sour foods like vinegar, pickles and olives.
Eat dry grains like crackers (corn thins or ryvita's are excellent) or dry oats, and dry vegies including broccoli, potatoes and cabbage. Steamed vegetables and mung beans, especially sprouted are an excellent everyday food. Sprouting them creates beneficial enzymes for your digestion.
Take hot and bitter spices like chili, pepper, tumeric and dry ginger powder to stimulate digestion. Drink hot ginger tea before meals. Food should not be taken before 10am or after 6pm.
The Veda's have one surefire way for losing weight. The patient must only eat whilst squatting!