First of all....
Now on to the nitty gritty:
Losing 50 pounds in 50 days is unrealistic for most people.
That would mean you would be losing a pound per day. Most people aren't able to do that unless they are losing weight in an unhealthy way (fad diets, and so on), or are very obese when they start.
And even then, it seems like the rate of weightloss will slow for most people as they get closer to their goal weight (or as their bodies rebel against an unhealthy fad diet). Many people experience plateaus where they will not drop a single ounce for weeks, or even months (or years), despite eating right and working out regularly.
A more realistic goal is to lose 1-3 pounds per week. Expect that your weight loss may not be consistant. For example: you may lose 3 pounds a week for a whole month, then nothing for a week, then maybe one pound after that, then five pounds after that.
Also, ditch the diet pills. I'm sure your friend believes they worked for him, but I'll bet if you questioned him further about it you would see that the
real reason he lost weight was because he changed some eating habits and/or got more exercise. You will hear it over and over here: there is no such thing as a magic weight loss pill.
As for what to eat, you need to start eating breakfast and lunch, along with little snacks throughout the day if you need them. Basically what you are doing by skipping breakfast and lunch is sending your body into starvation mode, so by the time dinner rolls around you are so ravenous you would eat anything put in front of you. Not good. Pop into some of the different diet forums here (like Adkins, Calorie Counters, etc) for more info about different eating plans, and see which ones you are interested in.
If you want specific examples of what to eat, then pop into the Living Maintenance forum and check out one of their accountability threads. The people who have successfully lost weight and kept it off will post what they have eaten that day. It will give you a blueprint of what you should be eating if you really are clueless about where to start.