I’m guessing Matt means in the beginning when a person is coming off a diet. But after that you should cut the PUFA out. Just make homemade “junk” food fried in coconut oil.
When it comes to “Junk” he means warming foods. Not all which are junk foods. Cheese, (pizza, grilled cheese, cheese burgers), coconut, chocolate, flour, red meat (beef, lamb), potatoes (sweet potatoes, yams), soy sauce, ice cream, cheese cake, cookies, pastries, pies, cakes, pretzels, potato or corn chips, cheese and crackers, salty popcorn. These will help raise your metabolism/body temperature if done in the right way.