Who is this blog for? I'm not sure how you are monetizing it, but if it is for human readers then I do NOT recommend publishing low quality content, or spun content. For a BLOG to be successful, you want subscribers, not just traffic. Nobody is going to sign up for "generic" content.
I'd really have to hear more about your full plan/goals before offering any in depth advice, and I wouldn't want to suggest anything you can't afford. It can be costly to work with a US quality writer (assuming you are targeting a US audience) but what you might consider is looking for somebody in the US who is a weight loss specialist in some way... maybe a personal trainer looking for some cash on the side? Anyone who is looking to share their expertise, so you end up with genuine/authentic/valuable content that people will trust.
What I might also recommend is having different features. Comics, for example, are very popular. Maybe there's a cartoonist for hire that can put together a weekly comic about weight loss- something that has potential to go viral but will also bring readers back. You could have various features: weekly recipes/meal plans, exercise charts, etc. I only say this because to me the keyword in your question is BLOG, and successful blogs depend on loyal readers- which depends on great content and you'll be wasting your time on anything generic.
Hope that helps