I love Ian's suggestion, except that I would recommended sticking with full-fat dairy products. I've read that they are better for you, because they are natural foods, and your body processes and utilizes them more easily/efficiently. High fat dairy is actually associated with a lower risk of obesity:

http://www.npr.org/blogs/thesalt/201...y-keep-us-lean

http://time.com/3734033/whole-milk-dairy-fat/

You're going for the gold, with a BMI goal of 18.6. That's a medically-accepted safe BMI. Best of luck - I'm trying to get there myself!

I agree with full-fat dairy, it has way less sugar in it and keeps you full much longer. For me, fat isn't the enemy, sugar is. Sugar makes me feel awful and really stalls weight loss, which is why I try to only consume sugar from fruits, vegetables and small amounts from dairy (like whole milk). But like I said, diets are different for everyone.

As far as the keto diet, which was mentioned as one of those diets that doesn't render permanent weightloss, I did that diet a while back for over a year as a way to control my epilepsy, and it's what got me off of sugar, and helped me realize that sugar was what my body was responding negatively to (it also helped decrease my seizures significantly). Again, I am not saying it will work for everyone, but for me -- I did the hardcore keto diet, and then gradually transitioned to a more forgiving low sugar/ moderately low carb diet and I kept all of that weight off (until I got pregnant) without any trouble. I think it's the transition out of eating keto-style and into a more manageable diet that trips people up, because it has to be a really slow transition with a heavy focus on increasing vegetables, adding fruit back in, and then gradually adding beans, nuts, etc. I was monitored by a doctor since my diet was not explicitly for weight loss, so I definitely had more at stake and having that medical monitoring and someone telling me exactly what percentages (fat/protein/carbs) to aim for each week was a huge benefit to keeping my weight and overall health stable.

Best diet for you depends on your goals. Are you looking to maximize your weight loss in a specific period of time? Are you looking for gradual life changes that you want to sustain beyond your goal weight? Are you looking to get your diet more in line with a personal philosophy? Do you have specific medical conditions that you should/must consider? All four examples will have 4 different "perfect diets".

Bottom line is that studies show that quick weight loss just as effective for permanent weight loss as is slow weight loss:

http://www.medicaldaily.com/theres-n...t-be-it-slow-o
r-fast-its-maintaining-weight-loss-over-307250

http://www.bariatricnews.net/?q=news...al-weight-loss

The key is in maintenance, not in speed of weight loss. Some studies show that it's easier to bootcamp it for a period of time then switch to maintenance for some dieters than it is to go long term as slow weight loss can be a significant demotivator. Others prefer to make minor changes and accept a slow rate of weight loss and still stick to their plan.

http://www.telegraph.co.uk/news/scie...ets-claim.html

Determine your weight loss goals (not goal weight, but how you want to lose it) and go from there. But ultimate success depends on a life-time weight management strategy.