Hi,
Congratulations on your motherhood. Stay fit n healthy. After knowing your concern, and also you are having hypothyroidism, reducing weight n getting back to your pre pregnancy weight might take little more time. But you need to be patient n stress free at this time of lactation.
I second the opinion of Dr. Gupta, she already suggested you a wonderful diet plan n regime. I would add a few more points to it. Do your stretching n few yoga along with walking. Among foods keep a check on intake of
sugar n high carb items. Have small n frequent meals, n keep your self well hydrated. Most importantly enjoy your motherhood, keep your baby mostly on breastfeeding, that too helps you in losing weight fast.