A problem with many conventional weight-loss programs such as Weight Watchers, Nutrisystem, etc. is that since they are based on reducing your calorie intake via portion control you quite likely will be hungry many times while you are on the plan. This can cause you to "cheat" and diminish the benefits of the program.
As Seth Roberts mentions in the book, you can use the SLD as a tool to help mitigate your hunger while on one of these other programs, thus decreasing your appetite and increasing your chances of success.
However, I think you do need to be careful about accounting for the caloric content of the oil.
For example 1tbs of ELOO contains 120 calories and 14 grams of fat. Using the Weight Watchers points formula, this would equate to 3.5 points per tablespoon, or in my case 14 points per day since I'm consuming 4 tbs. daily.
I would suspect that if you don't account for at least some of the points in the oil, and consume your full daily point allottment, you will actually end up overeating and not seeing much weight-loss.