FWIW I used this method successfully to get in the habit of flossing my teeth every night. It seems like every night after dinner I am tired and I have the same urge to skip flossing and just read a book, watch tv, hang out with my family, etc.

I started telling myself that whatever I decided to do was probably what I would end up doing every night. To my surprise, this worked like a charm.

I think flossing is especially amenable to TDT because you are in basically the exact same scenario every day, day after day after day.

With dieting it's probably trickier since there are a lot of different scenarios you are facing and it's hard to fit them into a reference class on the spur of the moment. For example, suppose your old college buddy you haven't seen in 10 years shows up and wants to get together for some beer and wings on the spur of the moment. Does that fall into the reference class of "drinking beer and eating bar food with a long lost friend who showed up after 5 or more years"? or perhaps "going out with a friend and eating wings"? or "eating unhealthy food on a special occasion"?

It's difficult to say. And for a typical working adult, there are dozens of potential diet-breaking special occasions in a year.

Based on my experience, I would say that TDT shows a lot of promise for combating akrasia. But in the context of dieting, someone needs to solve the reference class problem.