It seems that you can lose weight while eating ultra-processed food - but to a lesser extent than if you cut them out. Ultra-processed food lacks a set definition, but is generally considered to include ingredients that are never or rarely used in kitchens,

In a small trial, people lost more weight and fat while eating a diet rich in minimally processed foods than they did eating a diet high in ultra-processed foods.

Drop the ultra-processed foods, a new study says. People lost twice as much weight on a diet with minimally processed foods compared to one with ultra-processed products, even though both diets were nutritionally matched,