When it comes to weight gain, there are a lot of different factors that come into play. However, one of the most important things to consider is your diet. What you eat plays a big role in how much weight you gain and how quickly you gain it.If you're looking to put on some serious weight, then you need to make sure that you're eating high-protein non-vegetarian foods. These foods will help you pack on the pounds quickly and effectively. Here are some of the best high-protein non-vegetarian foods for weight gain: