One of the best ways is to get within these popular topics but do so by finding low competitive keywords to target within the niche. Most people in the niche will be focus on going for the big kahuna keywords so while they do this you can focus on the low competitive ones that people are still searching for. Another option of course is to find niches that people are indeed searching for but may not be as popular as weight loss etc. The choice is yours of course and you can choose based on your own preference. Just always go for low competitive terms, doesn't make sense to compete with the big boys as they tend to have a lot of cash to invest into getting good rankings.