hai, Smoking will not directly cause weight loss. eat protein nourished foods like Almond,cashew,channa,soyabean,peanut in your daily food intake. Add jaggery,black gram,and dal prepared with ghee. take diary product like milk,yogurt,chesse,butter etc. Add banana and tuber vegetables potato,arrowroot, etc. fig and dates,mango will advisable. high calorie food like ice creams ,milk Shakes will help in weight gain. If you eat non vegetarian food take meat and sea food once in two days. avoid stress,sleeplessness. This will nourish in a healthy way and gain weight. Thank you hope i answered your query