These may contain gluten directly or through cross-contamination, or they are very unhealthy.

Alcohol.
Amaranth.
Apple cider.
Artificial colors.
Artificial flavors.
Baking powder.
Barbecue sauce.
Barley.
Beans.
Bouillon cubes or stock cubes.
Boxed foods.
Bread.
Buckwheat.
Butter.
Cake.
Candy.
Canned soups.
Caramel color and flavoring.
Casein.
Cayenne pepper.
Cereal.
Cheese spreads and other processed cheese foods.
Cheese.
Chocolate (unless 100% cacao).
Coffee.
Cold cuts.
Coloring.
Cookies.
Corn bread.Corn chips.
Corn.
Cottage cheese.
Crackers.
Cream.
Creamer (non-dairy or dairy).
Dextrins.
Diglycerides.
Dip mixes.
Dry roasted nuts and honey roasted nuts.
Dry sauce mixes.
Eggplant.
Eggs.
Einkorn.
Emmer.
Emulsifiers.
Enzymes.
Extenders and binders.
Fast foods.
Fat replacers.
Flavorings.
Food starch.
French fries in restaurants.
Fruit juices.
Ghee.
Goat cheese.
Grapes.
Gravies.
Gravy cubes.
Grits.
Groat.
Honey hams.
Hydrogenated starch hydrolysate.
Hydrolyzed plant protein.
Hydrolyzed vegetable protein.
Hydroxypropylated starch.
Ice cream.
Instant mashed potatoes.
Instant teas and coffees.
Junk food.Ketchup.
Luncheon meat.
Maltodextrin.
Maltose.
Mayonnaise.
Milk.
Millet.
Miso.
Modified food starch.
MSG.
Muffins.
Mustard.
Natural colors.
Natural flavors.
Nut butter.
Nuts.
Oats.
Oil, frying.
Pancakes.
Paprika.
Pasta.
Pickles.
Pies.
Potatoes (white).
Pre-gelatinized starch.
Pretzels.
Processed crab.
Processed foods (spam, hot dogs, cold cuts).
Quinoa.
Relish.
Rice (except wild rice).
Rye.
Sauces.
Seasoning.
Seed butter.
Seeds.
Smoke flavors.
Sorghum.
Sour cream.
Soy sauce.Soy.
Spelt.
Stabilizers.
Starch.
Sweetened fruit juice.
Sweeteners (none except Stevia in moderation).
Tamari.
Teff.
Teriyaki sauce.
Textured vegetable protein.
Tomatoes.
Triticale.
Vegetable gum.
Vegetable protein.
Vinegar.
Vitamin supplements (check the labels carefully).
Waffles.
Wheat.
Whey.
Yogurt.