The best way to build an email list is by SPEAKING.
Go out and speak at your local library, the lions club, go speak at Toastmasters, go speak EVERYWHERE!
When you do speak just say “hey by the way… I have some tips on how to lose weight, share a personal story about how you lost 45 pounds this year. Explain you have tips on how you achieved that weight lost. Also say you give motivational tips on how you can TRANSFORMATION. If you need some kind of motivation or just a simple “pick me up” then sign up and to receive those free of charge. Then before you know it, you pass the clipboard around and now you have a collection of emails.