Friday, December 21, 2012
Fats. The good, the bad and the ugly!
Fat is an essential nutrient, as it plays a number of important roles in the body. However, I’m sure you know that an excess of fat can lead to many lifestyle-related conditions.
Not all fats are the same. There really is the good, the bad and the ugly!
- Only in animal products – ie. Full cream milk, cheese, butter and cream, liver, kidney, brains, prawns, squid, eggs.
- HDL (good)
- LDL (bad)
- Saturated fats are actually a greater threat to blood cholesterol levels than cholesterol itself!
- Cholesterol levels can be reduced by soluble fibre-rich foods (e.g. oats).
- Most common form of fats and oils in foods
- Glycerol + free fatty acids
- Stored in adipose tissue (fat tissue)
- Saturated fats, Polyunsaturated fats, Monounsaturated fats
· Saturated fats -
- From animal sources and solid at room temperature. – ie. Fatty meat and chicken (especially skin), processed meats, sausages, deep fried foods, full fat dairy products, cakes, biscuits and pastries, chocolate. (but note: palm oil (50% saturated) and coconut oil (90% saturated))
- Increase LDL cholesterol.
- Limit these.
· Polyunsaturated fats
- Plant and animal-based food. Liquid at room temperature.
- Omega 3 and Omega 6 = essential fatty acids (can’t be made by the body).
- Omega 3 – fish and seafood: health benefits: decreases blood clot risk, prevention and treatment of hypertension (high blood pressure), heart disease, arthritis and cancer. Often deficient in the diet.
- Omega 6 – safflower, sunflower, corn, soybean and cottonseed oil, also found in meat. Generally adequate in the diet.
- Use instead of saturated fats: dietary sources – vegetable oils, soy products, polyunsaturated margarine, nuts (walnuts, hazelnuts, brazil nuts), seeds (pumpkin, safflower, sunflower, sesame), fish and seafood.
· Monounsaturated fats
- Can reduce blood cholesterol, without lowering “good” cholesterol levels.
- Reduce the risk of heart disease
- Olive oil is also rich in antioxidants.
- Use in place of saturated fats.
- Dietary sources: monounsaturated margarine, olives and olive oil, canola oil, macadamia nut oil, avocado, nuts (peanuts, almonds, cashews), peanut butter.
- Choose these as your primary source of dietary fats.
Why a low fat diet??
Fat is more fattening than any other nutrient.
It costs 3-5% of energy to store dietary fat, where as to convert carbohydrate into body fat costs 25% of energy. Under normal physiological conditions, carbohydrate is not converted to fat. So, although increasing energy intake from any macronutrient (fat, protein or carbohydrate) will result in weight gain, this excess weight can be muscle and carbohydrate stores (glycogen) on a high carbohydrate diet.
Dietary fat is the last nutrient to be used for energy, hence the most likely to be stored when energy consumption is excessive.
Low fat diets are easier to stick to, as it does not need to be particularly restrictive, as many recipes are easily modifiable.
How to reduce fat in the diet
· Trim all visible fat from meat, or preferably, choose lean cuts of meat.
· Remove skin from chicken.
· Consume fish/seafood 2-3 times per week.
· Fill up on low GI breads, cereals, legumes, fruit and vegetables.
· Use small amounts of added fat (butter, margarine).
· Use low fat cooking methods (grilling, baking or dry frying).
· Limit take-away foods and fried foods.
· Use low-fat dairy products.
· Snack wisely on lower fat options.
· Learn to modify old “favourite” recipes.
But, for the record..
· When following a low fat diet, weight loss is predominantly fat loss, rather than muscle or water, so weight loss can be slower (though more likely to be permanent!) (0.5-1 kg per week is ideal)