Not all of us have this issue but losing weight too rapidly on the diet an be a real problem for some of us in the beginning. My suggestions are:
Eat 3 full meals plus 2 hearty snacks every day.
Rotate and eat starchy vegetables- potatoes, sweet potatoes, manioc, and any of the large variety of winter squashes including pumpkins.
Discover which non-gluten grains are OK for you-and try to vary them often. This includes quinoa, millet, amaranth, rices, wild rice (not actually a rice), buckwheat, and then explore how oatmeal and corn work for you. Some people cannot eat any of these two, some can with no problem, and some folks can have it occasionally.
Personally, I do better with less grains in my diet but in order to not lose weight, I have to eat large quantities of vegetables both raw and cooked. I need to regularly have a lot of starchy vegetables like beets, carrots, parsnips, rutabagas and turnips besides the other starchy veggies listed above..
Take your 4-10 teaspoons of flax or hemp seed oil every day, and use your low saturated fat oils sparingly as you cook.
In addition, use a daily probiotic to ensure you are metabolizing your foods. Take up to 5,000IU 's of Vitamin D every day, exercise appropriately for your level of symptoms, rest and sleep as much as you need, and ALWAYS reduce stress whenever possible.
If you are initially too rigid on the diet, you will lose weight rapidly and experience weakness. Healing cannot take place when your body is not getting enough nourishment. Experiment with foods and remember: eating is a meant to be a pleasurable experience not a punishment. Recovery can begin as soon as you find a healthy balance of filling vegetables, lean proteins, fruit in moderation, and grains appropriate for you.