Originally Answered: How can I gain muscle and lose fat at the same time? I want to gain weight as an result.?
ok in order to maximize your results you have to follow a super healthy diet and this of course will make you lose weight, but to balance out and not to lose a lot of weight you will have to use weight gainers.
About the diet, I suggest you follow the abs diet, (you can buy the book it is totaly worth it, just keep in mind that it is focused a little more on losing weight although also on gaining muscle) it recomends 12 groups of foods that are super good for you to both build muscle and lose fat. Here are the recomended foods:
Spinach, broccoli, all green veggies,
Dairy non or low fat (yogurt)
Instant oatmeal (natural, no sugar added)
Eggs (more whites than yolks)
Turkey, chicken breast, tuna
Whole grain bread, cereal, brown rice, wheat pasta
Extra whey protein (or weight gainers in your case)
Raspberries (all berries) apples, bananas, grapefruit
And it also has a few rules you have to follow like eating 6 times a day and some other stuff you'll have to consider.
The abs diet alone will boost your metabolism and will make it easier for you to gain muscle too. Regarding the workout program, in order to maximize muscle growth, try working 2 muscles per day on a back to back way, meaning biceps and triceps one day, chest and back the next day (back to back muscles) and let the muscles rest for a week. While you workout the muscles tissues get ripped and the muscle grows while resting, while repairing the tissues, not while working out and it takes 1 week to repair the tissues. you can find out more about this in the book Body for life, it has a lot of helful info.
So if you follow the abs diet and seriously workout you are probably going to end up losing weight (gaining a lot of muscle tho) but if you don't want to lose weight, here is where you add the weight gainers, I suggest you play it by ear while you see the results after every week, you don't want to over do it and end up gaining fat weight too.