What causes more weight gain – fat, calories, or sugar? Which fats are good and which are bad for your health?
Sean Cogdill, United States
The energy stored in our food is measured in terms of calories. Technically, one calorie is the amount of energy required to raise the temperature of 1 gram of water 1 degree Celsius (1.8 degrees Fahrenheit). The Calorie measure used commonly to discuss the energy content of food is actually a kilocalorie or 1000 real calories. For this reason, the Calorie in food is often written with a capital C. Different foods can be used by the body to produce different amounts of energy. Carbohydrate e.g. sugar contains less than 4 calories, whilst fat contains 9 calories per gram. This means 5 g sugar in a product has about 20 calories, whilst 5 g fat has 45 calories. Therefore a good way to decrease the calories in your food is to lower the amounts of fat. But just because a food is labelled fat-free, it doesn´t mean it is calorie-free. Indeed, most fat-free foods still provide a lot of calories from carbohydrates and proteins.
We must also remember that the human body needs a certain amount of oils for good health; because they contain fat soluble vitamins and nutritionally essential fatty acids. Fats can be either saturated or unsaturated (which includes mono-unsaturated and polyunsaturated). Most Saturated fats should be reduced because they raise blood cholesterol. Cholesterol is a fat-like substance found only in animal foods. Excess cholesterol furs up arteries and is linked to heart disease and strokes. Monounsaturated fats, found in abundance in olive oil and peanut oil, appear to protect against heart disease because they replace saturated fats in the diet. Polyunsaturated fats can be further divided into the omega-6 and the omega-3 families. Most Europeans already get plenty of omega-6 fats, since many vegetable oils contain them naturally. We are now being advised to eat more omega-3s, which are thought to have a positive impact on heart health and an important role in brain and eye function. Oily fish such as salmon, herring and mackerel are a good source of omega-3s, which are also found in walnuts and some oils like soybean and rapeseed.