Avocados

Avocados, like walnuts, are rich in heart-healthy omega-3 fats and fiber, which help fill you up without causing you to gain weight when eaten in moderation.
People who eat avocados have a lower body mass index (BMI), smaller waist and higher “good” HDL cholesterol levels than those who forgo them.

 Plus, half an avocado delivers 20 percent of your daily folate needs — a mineral that can be hard to come by.