I was born in 1964, at the beginning of the war on fat! Fatwas being touted as the bad actor in our diets, making us all fat. I grew up eating margarine because butter was bad. We drank skim milk because whole milk was unhealthy. We cut off all the saturated fat on our meat because it was contributing to high cholesterol and was way too gross! The scientific community convinced bakers and fast-food restaurants to stop using supposed cholesterol elevating saturated forms of coconut and palm oils and replace them with trans fats and polyunsaturated oils highly susceptible to rancidity. By the 1980’s we were all convinced healthy meant no or low fat due to poor studies and even worse interpretation of those studies. (1, 2) Big name society’s sent out recommendations on low-fat eating. I spent the 80’s in college getting a degree in dietetics and learning how a low-fat diet was key to good health and a carbohydrate diet of up to 75% carbs was good for you.
This trend in low-fat eating continued for the next 40 years! Unfortunately, we have been and still are way too trusting of people who supposedly know better than us. During that 40 year period, there was a significant increase in obesity, an explosion of people on cholesterol lowering drugs, and a marked increase in type 2 diabetes. (3) If a low-fat diet was effective at making everyone less fat, why the rise in obesity and diabetes? If a low-fat diet cut out the bad saturated fats that caused high cholesterol, why were so many people on cholesterol lowering drugs? Where did the vast disconnect occur to bring our society to the point where 1 in 4 deaths are associated with heart disease? (4)
Obviously, we were duped! Lots of propaganda and false claims went into marketing low-fat diets and unsaturated fats to keep us slim and healthy. However, studies and statistics are now showing quite the opposite. (5,6) Three points illustrate this fraudulent thinking
#1: Fat does not make you fat, carbohydrates make you fat!
In 1992 the U.S. Department of Agriculture introduced the Food Guide Pyramid encouraging Americans to eat carbohydrates like bread, cereal, rice, and pasta as the foundation of their diets and limit fats. Unfortunately, high carb diets cause blood glucose spikes which trigger the pancreas to release insulin. Insulin is a hormone that opens the cells to receive the breakdown of carbohydrates, or glucose, in the blood. The problem arises when the cells are constantly bombarded with insulin and eventually become resistant to it and refuse to open. This increases the blood glucose level and eventually leads to type 2 diabetes.
A second problem with the high carbohydrate diet arises when the cells are full and can no longer accommodate any more glucose. The glucose is then converted to fat and stored as adipose tissue. The fat in adipose tissue is metabolically active and produces it’s own set of hormones including leptin.
Leptin is an appetite suppressing hormone. It is released into the blood in high amounts in obese people. Satiety centers are bombarded by it and eventually become resistant to it just like cells become resistant to insulin. As a result, appetite is not suppressed and eating is not controlled. Weight gain ensues and weight loss becomes very difficult.
#2: Bad fats make you sick!
“Bad fats” like trans fats and some polyunsaturated vegetable oils make you sick. They raise cholesterol, increase inflammation and make you more susceptible to heart disease. Trans fats are vegetable oils that have been hydrogenated (added hydrogens) to increase shelf life, stabilize flavor, and guard against spoilage. They have been shown to increase bad cholesterol (LDL) and decrease good cholesterol (HDL). Trans fats are found in margarine, shortening, the oils used to cook fast food French fries, and commercial baked goods.
Polyunsaturated fats (PUFA’s) are mainly categorized into Omega-3 and Omega-6 fats, both essential because our bodies can’t make them. A mix of PUFA’s is found in foods, some favoring one type over the other. A high percent of omega-6 polyunsaturated fats are found in vegetables and seeds and processed into oils we use to cook. Due to processing and their unstable chemical bonds, they easily become rancid. This triggers free radical formation and inflammation in the body. It can also trigger a build up of cholesterol on blood vessel walls. Omega-6 polyunsaturated fats are essential for good health and can be obtained through food in the diet. However, processed oils like corn, soybean, sunflower, canola, and safflower are inflammatory and should be avoided in the diet.
#3: Good fats keep you full and energized!
Good fats found in wild fish, avocados, nuts and seeds, olives, and coconut oil do not spike blood sugar, help keep you satiated, are anti-inflammatory, and provide a good source of energy. MCT oil (medium-chain triglycerides) is another great source of fat that bypasses the lymph system and is readily absorbed by the blood. It is easily converted to ketones and a highly useable form of fat for the brain.
Fat is an important macronutrient and we should be eating more good fats in our diet while we cut out the inflammatory fats and high carbohydrate, glucose spiking foods. Although fat has been vilified, science is admitting the benefits of consuming good fats and avoiding the high carbohydrate foods that contribute to insulin resistance, type 2 diabetes, obesity, and heart disease. The real skinny on fat is just that, it will actually keep you skinny!
1. https://www.sevencountriesstudy.com/about-the-study/investigators/ancel- keys/
2. https://www.nfb.org/sites/www.nfb.org/files/images/nfb/publications/vodold/ vspr9804.htm
3. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(16)00618-8/ fulltext.
5. https://www.hsph.harvard.edu/news/hsph-in-the-news/have-low-fat-diets- made-us-fatter/
6. https://www.hsph.harvard.edu/obesity-prevention-source/obesity-causes/diet- and-weight/.
7. https://bmccardiovascdisord.biomedcentral.com/articles/10.1186/ s12872-018-0941-y