An obese, 25-year-old G1P0 comes to your office at 8 weeks gestational age for her first prenatal visit. She is delighted to be pregnant and wants to do whatever is necessary to ensure a healthy pregnancy. She is currently 5 ft, 2 in. tall and weighs 300 lb. She is concerned because she is overweight and wants you to help her with a strict exercise and diet regimen so that she can be healthier during the pregnancy. During your counseling session with the patient, you advise her of all of the following except