I posted this 3 years ago but the question comes up a lot so I’m reposting it.

From Chapter 13 of Dr. McDougall’s The Starch Solution:

• The core of the diet focuses on eating starches complemented with nonstarchy vegetables and fruit.
• The diet excludes all animal foods (meat, poultry, fish, dairy, eggs) and all isolated fats and oils, including olive oil.
• It does not restrict calories or limit eating. You eat until you are satisfied. If you are hungry an hour later, you eat again.
• Foods can be combined in any way, with any preparation.

Starches are grains, legumes, and starchy vegetables:

• Grains include barley, rice, whole or bulgar wheat, farro, corn, millet, oats, rye, spelt, triticale, amaranth, quinoa. You can eat the grain or products made from the grain.
• Legumes include all beans (adzuki, black, navy, pinto, kidney, cannellini, chickpeas, great northern, lima, mung, soybeans), peas (black-eyed peas, split green and yellow peas), lentils (green, red, brown). Although peanuts are a legume, they “should be minimized or avoided altogether, especially if you are trying to lose weight.”
• Starchy vegetables include potatoes, root vegetables, and winter squashes. That includes potatoes, sweet potatoes, yams, burdock, cassava, taro, and all the squashes: acorn, kabocha, butternut, kuri, Hubbard, pumpkin, etc.).

Nonstarchy vegetables are summer squashes (zucchini, patty pan, yellow), root vegetables (carrots, beets, jicama, radishes, onions, garlic, fennel, ginger, turmeric), beans (green beans, snap peas, snow peas), mushrooms, and other plants (broccoli, cauliflower, cabbage, asparagus, celery, rhubarb, lettuce, kale, collards, spinach, eggplant, tomato, cucumber).

Fruit. You name it, but avocados, olives, and dried fruits, should be minimized or avoided altogether especially if you are trying to lose weight.

In the above description of what to eat, I named three foods that McDougall flags – peanuts, avocados, and olives. Here is his full flagged list along with his reasoning:

There are a few foods that won’t spoil your success with the Starch Solution, but will slow your progress. If you seek to accelerate your weight loss, or if you suffer from a chronic disease or are on the cusp of developing one, I recommend avoiding these foods altogether. If, on the other hand, you are already happy with your weight or not in a hurry to lose, and you do not suffer from chronic illness, you might wish to consider including small quantities of these higher calorie foods in your starch-based meals:

• Avocados
• Dried fruits
• Flours (whole grain, white, all-purpose)
• Fruits and vegetable juices
• Nuts
• Peanuts and peanut butter
• Seeds
• Simple sugars (table sugar, maple syrup, molasses, agave)

In my experience, the last thing to go for people is oil. They continue to use oil to cook with and as a dressing. There is evidence that a combination of carbohydrates and fat is worse (puts weight on faster, raises blood glucose) than eating carbohydrate or fat alone.

Packaged and processed foods are part of this diet as long as they don’t include animal products. Oatmeal, pasta, whole grain breads, canned or dehydrated beans and soups, jarred sauces and bean dips, frozen vegetables, frozen entrees … it’s all in there.