Will gaining weight replace the need for fillers?

While we know that dramatic weight loss can make your face look older (see my link below for a dramatic example), it is not as clear if weight gain will make you look younger because it is difficult to predict exactly how the facial fat gain will be distributed.  As long as your weight gain is supervised by a medical professional my best advice is to wait until you reach a healthy and stable weight and then decide if and where you need enhancement. Good luck to you.

Weight gain often adds weight all over. It would not be surprising if your face looks a bit fuller after a 20 lb gain.

Dear "BigChin:"   If you are under the age of 40, you may be very satisfied with your "gaunt" appearance after a bit of weight gain, because increasing the amount of fat in the fat compartments of the face will correct the problem at its source. However, as we age, our faces become saggy, lax, furrowed or less defined (for example, around the jaw) due to the loss of bone more than due to the loss of fat. So, replacing the lost volume at the sites where it has diminished, via targeted filler injections, will give you a more natural, youthful, and sculpted appearance than can result from gaining weight.All the best to you,Dr. Clark

I would say that its impossible to predict this. I think that aging is the most important factor. We know that fat pads under the skin do things as we age. Good luck with your nutritional  efforts! Most people would love to have your problem....as most people eat TOO MUCH :)