Jillian Foley is a registered dietitian and is the owner of Nutritionista. She started out working in a gym working with folks that wanted to diet or sports nutrition. She now specializes in weight management and related diseases, as well as sports nutrition. Jillian does this through assessing strengths and weaknesses, goals setting, building of healthy habits and accountability.  
Jillian explained that weight management is 20% is exercise and 80% is nutrition. The nutrition part is then 20% food education and 80% psychological  
The psychological part is where Jillian focuses, explaining that what we think is a lack of will power is often the bodies hormonal response to hunger.
Jillian then explained the food groups:
Protein - Preferably lean protein with low saturated fat. Nuts are great but have high calories and saturated fat. Eggs are also a great source of protein but the yolks are high in cholesterol, although gran fed chickens yolks have less.
Starchy carbohydrates - The way we prepare carbs is often the reason they are so high in calories. Healthy whole grain carbs are good for you
Vegetables - They create fulness full of vitamins and minerals. Be aware of dressings, especially oils
Fruit - Part of your carbohydrate intake
Jillian explained that approximately we should aim for three servings of dairy a day, and 50% of our diet to be healthy carbohydrates.