WEEK 4 - FATS (fatty acids / lipids)

· 9 calories per gram

· 20-35% of daily calories

· Not soluble in water

· 4 main types: saturated, polyunsaturated, monounsaturated, and trans fats.

· Body fat is called adipose tissue

Fat is an essential macronutrient with a many important functions within the body:

• Gives us energy. Fat is energy-dense, meaning it contains a lot of energy in a small quantity compared to protein and carbohydrates. But note, this can make it easy to eat more than we need.

• Builds healthy cell walls and maximizes the absorption of fat-soluble vitamins (Vitamins A, D, E and K) and fat-soluble antioxidants (such as lycopene and beta-carotene).

• Essential for supplying the body with omega 3 and omega 6 essential fatty acids

Saturated fat

Saturated fat increases total cholesterol by increasing the ‘bad’ LDL cholesterol, so it should be eaten in the smallest amounts.

Sources: Butter, cheese, meat fat, ghee, meat products (sausages, hamburgers), full-fat milk and yogurt, pies, pastries, biscuits, cakes, lard, dripping, hard margarines and baking fats, coconut and palm oil.

Monounsaturated fats

Monounsaturated fats appear to protect against heart disease, by increasing the levels of ‘good’ HDL cholesterol.

Sources: olive oil, avocado and avocado oil, canola oil, nuts (pistachio, almonds, hazelnuts, macadamia, cashew, pecan, peanut) and the oils from these nuts.

Polyunsaturated fats

Polyunsaturated fats can help lower your LDL (bad) cholesterol. Polyunsaturated fats include the essential omega–3 and omega–6 fats. They are essential as we have to get them in our diet our body cannot make them.

Omega-3 fats have a positive impact on heart health and an important role in brain and eye function. They are necessary for the growth and the synthesis of hormone-type compounds.

Sources: sunflower seeds, wheat germ, sesame, walnuts, soybean, corn, and their oils, certain margarines.

Omega-3 can be further divided into two forms:

• Long-chain omega-3 are found in oily fish (salmon, mackerel, herring, trout), mussels

• Short-chain omega-3 are found mostly in plant foods like walnuts, canola oil, soybean, flaxseed, and their oils

Trans fats

Trans fat are a very harmful type of fat (even more so than saturated fat) as it not only increases ‘bad’ LDL cholesterol, but it also decreases ‘good’ HDL cholesterol. Since 2018, the USA’s FDA has banned the addition of trans fat to food products.

Sources:

• Artificial trans-fats are formed when liquid vegetable oils are processed with hydrogen to make them into solid, shelf-stable products such as shortenings and margarines. This process is called partial hydrogenation. However, because trans fats are so harmful, food manufacturers now use a different process called ‘full hydrogenation’ which does not produce much trans-fat. Therefore, most margarine and shortenings nowadays do not contain any significant amount of trans-fat.

• Trace amounts can be produced in the heating and frying of oils at high temperatures.

• Trace amounts of ‘naturally occurring’ trans-fat are also found naturally in beef, mutton, lamb and dairy fat.

BODY FAT AND HOW TO LOSE IT

Fat cells are used primarily for energy to work the muscles and move the body. In addition, energy stored as fat also helps insulate the body and protect its vital organs.

When you consume more calories than your body needs, however, the excess energy remains stored. The stored energy (triglycerides) is collected as fat (lipid) within the individual fat cells, which slowly accumulate over time and result in weight gain.

The lungs are the primary organ used to remove fat from your body. During the energy conversion process, fat leaves the body either as carbon dioxide when you exhale, or as water in the form of urine or sweat. Body fat does not turn into muscle or exit the body through the colon.

During the fat-burning process, the body converts fat into usable energy, which causes the fat cell to shrink in size. The stored fatty acids are broken down, which releases energy and converts them into carbon dioxide (CO2) and water (H2O). This metabolic energy conversion also generates heat, which helps to control the body's temperature.

According to research, there are a number of enzymes and biochemical steps involved to completely break down a single triglyceride molecule. Some of the fat is available for usable energy. Carbon dioxide and water are essentially waste products in the fat-burning process, and most of the fat is expelled from the body as CO2.

When fat leaves the body, 84% is exhaled as CO2 and the remaining 16% is excreted as water. So most of the fat we burn is literally released into the air.

When combined with a healthy, balanced diet filled with nutrient-dense foods, physical activity is probably the best thing you can do to get your heart rate up and increase your oxygen intake, which can help promote fat loss. Keep in mind that you'll still need to burn more calories than you're consuming to create a calorie deficit in order to lose weight.

Exercise increases your metabolism or the rate your body uses energy. You can use up more stored fat by performing physical activities that double your metabolic rate—for example, swapping out one hour of rest with exercises like brisk walking or light jogging.

The American College of Sports Medicine (ACSM) and the Centers for Disease Control and Prevention (CDC) recommend at least 150 minutes of moderate-intensity exercise per week, plus at least two days of strength training to promote both weight loss and weight management.

Your body is also hard at work removing CO2 while you sleep, and research shows that poor sleep quality is a common cause of weight gain. Not getting enough sleep can also affect your ability to lose weight.

Weight loss usually causes a gradual reduction in body fat all over the body. To successfully lose weight, a reduction of 500 calories per day is typically recommended, though this number can also vary based on certain factors like age, sex, weight, height, and level of physical activity.

Counting calories and staying within your recommended daily range combined with a consistent exercise regimen are the best ways to promote a healthy, sustainable rate of weight loss.