Eat Lots of Nonstarchy Veggies
Along with your starches like potatoes and whole grains, Dr. McDougall recommends increasing the amount of nonstarchy veggies you're eating. This includes cooked and raw greens, carrots, cabbage, broccoli, cauliflower, yellow squash, zucchini, peppers, celery, cucumbers, mushrooms, and tomatoes. These have a low-calorie density and are packed with fiber and water, which means eating them will fill you up for not a lot of calories.
Note that Dr. McDougall says you shouldn't only eat nonstarchy veggies, because you need starches to feel satiated. This is a starch-based diet, after all! Eating only raw salads and steamed broccoli will leave you hungry and feeling deprived, and you'll end up falling off the plan completely.