If you absolutely had to choose a diet pill which ones would you recommend?

None. I do not know of any diet pill that is both safe and effective so that I do not recommend any.
Lose wt. The best to lose weight is to eat less food-calories. Exercise is secondary but helps. Especially to maintain weight loss. Eating less is diffiicult because you are really hungry 75% of the time. You are not lazy or crazyyou are just more hungry for various reasons--genetics, body chemistry. Don't blame yourself. Just get started. Physicians experienced with medical wt. Loss are called bariatricians.
OTC. The only medication otc that could possibly work well would be hoodia, but because hoodia is declared by the fda to be a food supplement it's potentcy--authenticity as a medication is not regulated. A pharmaceutical co. In europe has purchased the patent rights of the purified ingredient of hoodia. There has been a standstill as far as development of this potential weight loss medication.
Medical Management. There are no known diet pills that have been adequately researched over the counter. As a prescription med, Phentermine, given by an experienced physician is far safer Plan B than bariatric surgery. I have utilized Phentermine by rx. For patients for 17 years plus. The drug should not be prescribed by a physician without adequate experience with this medication. The drug is not an amphetamine.