No idea who he is but I NEVER download random apps to get someone's opinion about something. WAY too many frauds online and just about anyone can start an app or website and post all sorts of wild opinions about foods even if they have NO idea what they are talking about. Funny how eating a sensible/well-balanced diet has never gone out of style, but diet fads come/go. Being a 'paid advertiser' is what a lot of these people are, so whatever products they are pushing looks more like an ad than sound nutritional advice.
People who are mainly interested in making money off of their website/app are probably more concerned about how many 'followers' they have vs. providing sound/rational/accurate advice. Also have no idea what sort of education or background this person has to provide such information. You can waste a LOT of time researching people who pop-up online trying to decide if they are credible or not. I prefer to stick with known/reputable websites so I don't have to try figure out if they providing good/bad advice