What are the key factors that consumers should consider when evaluating the credibility of dietary recommendations provided by meal delivery services promoting keto, low-carb, or paleo diets, and how can they effectively distinguish between evidence-based advice and marketing-driven claims? Should consumers prioritize services that employ registered dietitians or certified nutritionists, or are there other credentials that are equally important? How can consumers critically evaluate the scientific evidence cited by these services to support their dietary recommendations, and what red flags should they watch out for when reviewing the research? Are there any specific nutritional or health claims that are commonly made by these services that consumers should be particularly skeptical of, and how can they verify the accuracy of these claims? By what criteria can consumers assess the transparency and accountability of meal delivery services in terms of their dietary recommendations, and what recourse do consumers have if they feel that a service has made false or misleading claims?