I have a goal to lose 50 pounds by July. I weigh 200 pounds and am 30 years old. I am 5'8 and my weight is distrubted evenly, thankfully.

Ive never been this overweight and I honestly am clueless about weight loss. I have tendinitis in both feet and have trouble walking long distances.

Here's my plan:

To briskly walk every day only 15 minutes (thats all i can tolerate) and alter my eating habits; but therein lies the other problem - Not sure what foods to buy (besides the obvious fruit/veggies).
And last, to do bicep curls - 20 reps of ten pound weights.

I do not know if walking 15 mins a day is sufficient enough for 50 pound weight loss, so i need some advice as to other things I can do to reap the most benefit.

Thank you for your input in advance! I do choose best answer!