Brief Answer:
low calorie diet with exercises
Detailed Answer:
Hello XXXXXXX 
Thank you for posting the query.
Weight gain is a common in 
thyroid disorders, as in thyroid the BMR, 
basal metabolic rate, is greatly reduced and we start gaining weight. Our lifestyle also plays a role in complicating the situation. Like in your case the sitting job decreases the BMR further. 
Therefore, it is important to ensure that you get just the right calories from food and burn the extra ones while exercising.  However, making positive changes for increasing the metabolic rate is equally important.
For your convenience, here are some  point wise dietary guidelines that may help you in meal planning:
•	Avoid simple sugars like 
glucose, honey, candies, sugar, chocolates, ice creams, fried food like samosa, bhatura etc. and refined food like white bread. Excessive intake of dry fruits and nuts like almond, apricot, resins and cashew and  Fatty dairy products like cheese, cream. Mayonnaise and butter are calorie dense and hence, best be avoided. 
•	Restrict the intake of Fruits rich in carbohydrates like mango, sapota, grapes, banana, custard XXXXXXX and litchi and vegetables like potato, colocasia (arbi), yam (jimikand), seetaphal and tapioca. Eat the allowed fruits along with the skin, as the skin is rich in fiber.
•	Ensure a sufficient intake of raw vegetables and salads as they add the much needed fiber to the diet. Facilitates regular bowl movements and support 
weight loss by regulating the calorie intake. Include the cooked beans and peas and whole grain products in the diet.
•	Restrict the excessive intake of foods like white bread and buns, cakes and cookies as these are mostly made with refined flour and contain Trans and Saturated fat and sugar.
•	Vegetable oils like soybean, mustard, canola, safflower, rice XXXXXXX  olive and corn oil are good sources of 
unsaturated fat. The intake of these should be limited to 5-6 tsp. per day.
•	Add legumes and pulses in the diet to ensure sufficient protein supply. Low fat milk and its products are also good sources. Avoid Soy and its products, these are found to interfere with thyroid gland function.
•	Avoid the Goiterogenic foods like broccoli, cabbage, iodized salt, cauliflower, XXXXXXX  mustard greens and turnip in raw form. You my however take these in cooked form. Also limit the intake of coffee and its preparations. 
•	Drink water and other drinks like sugar free lemon juice and clear soups to keep the body hydrated. It is highly recommended to 
•	Consider taking  small and frequent meals. 
•	If you eat non – vegetarian foods, stick to leaner options of fish and chicken and avoid egg yolk. Red meat and organ meats are a strict NO.
•	Include antioxidants in your diet. A liberal intake of fresh fruits and vegetables would provide its sufficient quantities.  Also include green tea in your daily routine as this helps in boosting the 
metabolism.
•	Exercises are also equally important, not only for 
weight management bit it also improves metabolism and regulated thyroid secretion. Get involved in activities like playing badminton, cycling, swimming, XXXXXXX walk  etc. This would save your activity routine from becoming monotonous. 
Hope this satisfies your query.
Meenakshi