So, as you're looking at these top ranked websites for the search term "weight loss", you should try to find websites with a Page Rank of 5 or higher.
Once you've found several websites like this, you should check and see whether or not they have links pages. Usually you'll see links from their index page that say (resources, links,related sites, etc.) Now, you need to search their website for their contact information or information on getting a link from one of their high Page Rank webpages.
Once you find their contact information you should send them an email asking if they will link to your website in return for you linking back to their website. If you do this correctly and professionally, they will respond and will place a link on their website to yours.
If you can manage to get 1 PR5 website to link to your website, you will be indexed by Google in under 3 days. If you can get 1 PR6 website to link to you, then you will be in Google's index in under 24 hours!
Support