You could incorporate it into your diet in the form of salad dressing and the such. A tablespoon is a great starting point. I like to use virgin coconut oil, olive oil and flax everyday. My skin has never been in such good shape. I don't think it is enough to contribute to weight gain as it is a necessary part of your diet anyway.
Do you eat dairy? If so, I like to mix flax and cottage cheese or yogurt together with Schulze superfood and use it as a dip or burrito filling. Even without the superfood it is tasty. I add Seasalt to it too, chopped garlic , onion, herbs if I have them.