Task: Question Answering
Input (English): Background Paragraph: Although some lipids in the diet are essential, excess dietary lipids can be harmful. Because lipids are very high in energy, eating too many may lead to unhealthy weight gain. A high-fat diet may also increase lipid levels in the blood. This, in turn, can increase the risk for health problems such as cardiovascular disease. The dietary lipids of most concern are saturated fatty acids, trans fats, and cholesterol. For example, cholesterol is the lipid mainly responsible for narrowing arteries and causing the disease atherosclerosis. 
Story: Two groups of people were part of a science study. Group A ate lots of fats(lipids), while Group B  had a more balanced diet with few fats. Group A gained a lot of weight over the course of the 6 month study. 
Question: Which group didn't eat excess lipids?
Output (English): Group B.