Aaaaand… drum roll… here are the answers!
1. Predominant fat in lard is monounsaturated. Yes, just like in olive oil. The composition of lard is as follows:
Saturated fat – 38-43%
Monounsaturated fat – 47-50%
Polyunsaturated fat 6-10%
It is a common misconception that animal fat = saturated fat. Most animal fats like lard or beef tallow have loads of monounsaturated fatty acids. Even butter contains around 30%. In addition 12-15% of saturated fat in lard is in form of stearic acid, which is converted by the liver to oleic acid( = more monounsaturated fat!).
2. Saturated fat consumption has decreased over the last 100 years.
According to this paper, published in the American Journal of Clinical Nutrition, saturated fat consumption in the US reduced from 16.6% in 1950-1959 down to 11.8% in 1980-1985. At the same time period the number of obese people has increased from 9.7% to 35% in women (33% in men).
3. Triglycerides are blood fats measured when you have a cholesterol test or a lipid profile test. It is very tempting to reason that fat in the diet raises fat in your blood. Sounds so simple and logical? But… The diet component most responsible for high triglycerides is carbohydrates. Consumed in excess, they get converted in the liver into triglycerides and transported to fat tissue for storage. The process is called “de novo lipogenesis” (new fat formation). Dr William Davies, a cardiologist from the US, describes it well here.
4. HDL is sometimes called “good cholesterol” and we are advised to eat foods which increase HDL to reduce our risk of heart disease. Low carb diets are found to raise HDL.
5. Glycemic index classifies carbohydrates by how much they raise blood glucose. We are told to stick to low GI foods for weight loss and diabetes management.
Baked potato – 101
“Frosties” – 55
“Peanut M&M’s” – 33
Muesli bar with dried fruit – 61
Super supreme pan pizza – 36
Eggs – 0
It seems blindingly obvious that GI system has major flaws as nobody in their right mind would consider M&M’s healthier than a potato. Eggs, beef, lamb, pork and other animal products have a GI of zero.
6. Cholesterol levels are tightly regulated in our bodies as this substance performs many vital functions. Up to 80% of cholesterol is synthesized in the body with 20% coming from dietary sources. When you reduce dietary sources of cholesterol, your cells try to increase their own cholesterol production to make up the difference.
7. Our heart prefers fat in form of fatty acids as its main fuel source. Ketones, which are formed when the body burns fats, make up around 1/3 of the heart’s requirements. During fasting conditions, they provide up to 60-70% of the heart’s energy.
8. Vitamin A (retinol) is a fat-soluble vitamin essential for growth and repair, healthy bones and teeth, good eyesight, thyroid and immune system.
Vitamin A concentration in mcg for 100 g:
Full fat milk 28
Sweet potato 700
Carrots and sweet potatoes are traditionally advised as a good source of vitamin A. However vitamin A in plants is in the form on beta-carotene which has to be converted to retinol at a ratio of 6:1. In addition, your body needs fat to absorb vitamin A. So slather some butter on those veggies!
9. It is a common misconception that your body needs a constant top-up of carbohydrates to keep the bloods sugar up. If I could have a dollar for every time I heard someone say: “My blood sugar is dropping after my gym session. I better get a Gatorade/piece of fruit/cereal bar”. Somehow I don’t think that our ancestors were munching every 3-4 hours to avoid a blood sugar drop. Any biochemistry textbook will tell you that our body has several hormones, the job of which is to keep your blood sugar up. They do it by switching to fat-burning for energy, releasing glycogen (stored form of glucose) into the blood and using ketones to provide energy for the brain. Muscle protein is spared for as long as possible.
10. Saturated fats and trans fats are often lumped together although they have vastly different structure and effects on the body. The only thing they have in common is that they are solid at room temperature. Trans fats are highly processed vegetable oils, hydrogenated to resemble butter. They have been linked to obesity, heart disease and cancer. Mary G. Enig, a renowned expert in lipid biochemistry, gives an excellent explanation on fats here.
So how did you go? Please send me some comments with your thoughts: what you knew, what surprised you, what you want me to cover in greater detail.
I am still working on Resources page but I promise to get it going soon.