Limiting portions can help you lose weight and ultimately prevent complications. A 2004 study of 329 overweight people found that 38% of those who practiced portion control for two years lost 5% or more of body weight, compared with 33% of participants who did not (they gained 5% or more of body weight). Learning what a portion size actually is—and eating that amount—is tricky. Do research and understand the basic terms of nutrition – calorie, portion, gram, tea and table spoon, one cup, ounce, liter…. all these will help to control the food intake.