It was earlier thought that the key to weight loss was eliminating all high carbohydrate foods, including pasta, rice and potatoes. We now know that carbohydrates are the body’s preferred energy source. Eating a potato, or any type of carbohydrate rich food, won't automatically make you fatter. However, if you are watching your weight, enjoy potatoes in moderate quantities and be careful of how you eat your potato (for example, fried, or as chips or wafers).
Fats contain approximately double the amount of calories per gram than carbohydrates or protein. They are a very concentrated form of energy. If you eat a lot of fat, you are more likely to put on weight than if you eat a lot of carbohydrate.