Studying human diet is notoriously difficult. Randomizing people who want to lose weight to 'keep doing everything how you have been' is not going to be a study

Studying human diet is notoriously difficult. Randomizing people who want to lose weight to 'keep doing everything how you have been' is not going to be a study that anyone enrolls in, so I think this study's methodology was thoughtful and realistic. The only genuine methodological critique I'm aware of for this study is its sample size.