s carbs and protein ingested along with insulin and converts these macro’s into fat and stores it as energy in our adipose tissue. (Spoiler alert: fats themselves do not necessarily make you fat). Too many calories, from any macronutrient, can lead to weight gain – therefore, moderation is the key.
Fun Fat Fact– A typical adult has approximately 50 billion fat cells … which means there are over six times more fat cells in one human body than there are people on the earth.?
What does fat do for us? Why is it so important?
- Our stored fat is our biggest energy reserve
Fat is a major fuel source for our body during inactivity and during exercise performed at or below 65 percent of aerobic capacity. This means that adipose tissue provides a lot of calories at low heart rates. Even at rest, fat contributes 50 percent or more of the fuel that muscles need, therefore slowing the use of our limited glycogen stores during low intensity activity and rest. (See table 1). Fat aids endurance by sparing glycogen reserves. Generally, as the duration or time spent exercising increases, intensity decreases (making more oxygen available to cells), and fat becomes the more important fuel source. Stored carbohydrate (muscle and liver glycogen) are subsequently used at a slower rate, thereby delaying the onset of fatigue and prolonging the activity. 
|Table 1 – Estimated Energy Stores in Humans|
|Energy Source||Storage Site||Approximate Energy (Kcal)|
|Fat||Serum free fatty acids||7|
|*ATP/CP = adenosine triphosphate/creatine phosphate|
- Dietary fat supplies the body with essential fatty acids, (EFA’s)
These are special types of “good fat”. Think omega-3 fatty acids!! EFA’s offer the crucial DHA and EPA primarily found in fish.
- Protects vital organs and is insulation for warmth
Some degree of fat on the body is healthy and necessary. It protects our vital organs by providing physical cushioning and stability and helps us maintain a constant core temperature.
- The backbone to important hormones
Cholesterol is what we call the parent hormone – it’s the backbone on which progesterone, DHEA, testosterone and our estrogens are made from.
- Fat is important in brain health
Fat surrounds neurons and allows electrical signals to flow efficiently, giving us the ability to think and act quickly. 60% of our brain is fat and it’s the quality of healthy fats that are linked to improved cognitive function, not the quantity.
- Assists in the absorption of fat-soluble vitamins A,D,E and K
Fat-soluble vitamins will not dissolve in water. Instead, fat-soluble vitamins absorb best when taken with or in higher-fat foods. (We will talk more about these in Part 6 next week)
- Maintain cell membranes
Vital for every cell in our body
- Maintain healthy blood cholesterol
Knowing which fats lower your bad LDL cholesterol and increase your good HDL cholesterol can help keep your heart and arteries in good health
Foods we eat that are high in saturated and trans fats promote inflammation. It’s best to minimize the amount of these foods
Fun Fat Fact – First the good news…fat cells generally do not increase in number after puberty so even if you gain weight the number of fat cells you have remains the same. Now the bad news… Each fat cell simply gets bigger and can expand up to ten times its normal size. ?
There is “good fat” (unsaturated fats) and “bad fat” (saturated fats). What are the differences?
A) Good fats – Unsaturated Fat
Unsaturated fats are considered the good“healthy fats” when eaten in moderation. They help increase your good cholesterol – HDL, which lowers your bad cholesterol – LDL. This helps reduce your risk of coronary artery disease and provides many other health benefits. Typically, unsaturated fats are liquid at room temperature (e.g. olive oil). They mainly come from plant-based sources like nuts, seeds, and vegetable oils, as well as fish. They can be further categorized as:
- Monounsaturated fats (MUFA’s)
This type of unsaturated fat contains only one – mono – double bond in its structure, thus fewer hydrogen atoms. MUFA’s are typically liqu