Anyone who's spent time on keto-focused subreddits has surely come across MCT oil, a.k.a. the key trendy ingredient in bulletproof coffee. Proponents say it can help speed up fat burn (and ultimately weight loss)—but is the hype legit? First, tell me what MCT oil...

This summer, people aren’t just slathering aloe vera on their sun-scorched skin. They're chugging it in hopes of losing weight, too. Aloe juice or aloe water—which can be found at health food stores—isn't as goopy or neon green as the stuff from the pharmacy, but it’s...