the inside out. >> reporter: ambrose was sprinting towards success. >> i never really felt deprived on the diet where every other diet i felt i was sacrificing to follow the diet. >> reporter: but some nutritionists say it's not all a dash to the finish. >> it's not a one size fits all. it's important to consult with a registered dietitian or physician, someone who really understands how to shape that plan to fit your particular health needs. >> reporter: since 2009, ambrose has lost a total of 90 pounds. >> i just felt healthier. i wanted to move more. i'm no longer hypertensive. >> reporter: sara haines, abc news, new york. >> interesting concept. we asked a little earlier, what are your resolutions for 2015? log on to wnnfans.com and let us know. >> do you have a new year's resolution? >> not yet. yours? >> my resolution is to make it to the next commercial break and return back in time. >> we'll see how that works out.