The following foods are high in fat: 1  Margarine, butter and other spreading fats including reduced fat spreads (although these contain less fat and calories they should still only be used in small amounts). 2  Cooking oils and oil-based salad dressings.3  Mayonnaise.4  Cream. 5  Fried foods including fried chips.hese foods can be eaten in small amounts as part of a healthy, varied diet. Foods such as cakes, pastries, biscuits, chocolate, crisps, fried foods and non-diet fizzy drinks should be considered as treats and only eaten occasionally.