Why Healthy Fats Should Be A Part Of Your Diet
For decades, we've been hearing about the dangers of dietary fat. Yet, the link between dietary fat and illnesses like heart disease has never been conclusively shown to be true.1 In fact, Dr. William Castelli, former director of the Framingham Heart Study, admitted that "we found that the more saturated fat that one ate, the more cholesterol that one ate, the more calories that one ate, the lower the person's serum cholesterol. ... We found that people who ate the most cholesterol, ate the most saturated fat, ate the most calories, weighed the least and were the most physically active".2 But don't order the steak and fries just yet. The reality is that there are good fats and there are bad fats and understanding the difference between them is essential for good health.
What Makes Fat Good
Fat plays an important role in your body. The walls of every cell in your body contain saturated fat. Fat also aids in the proper functioning of your nerves, lungs, liver, bones and immune system. The production of certain hormones and neurotransmitters as well as the absorption of vitamins A, D, E, and K requires fat. Moreover, your brain is more than 70% fat.3
Fat is basically composed of fatty acid and glycerol. Triglycerides are the most common type of fat found in our bodies and in the foods we eat. Triglycerides are so named because their composition includes three fatty acids. All fats (referred to here as fatty acids) contain a mixture of different characteristics and are categorized according to the predominant characteristic:
Saturated Fatty Acids: Animal fat is an example of saturated fat as are such tropical oils as coconut and palm oil and cocoa butter. The chemical structure of saturated fats makes them highly stable and, thus, suitable for cooking at high temperatures. They also help our bodies to utilize the unsaturated omega 3 and 6 fatty acids.
Monounsaturated Fatty Acids: Most nuts (almonds, pecans, cashews, peanuts, hazelnuts, macadamia nuts), avocados, olive oil, canola oil (which also has some polyunsaturated fatty acids), safflower oil. This type of fatty acid does not become rancid easily and is stable for cooking at low temperatures. Since canola oil has a higher amount of polyunsaturated fat as compared to olive oil and palm oil, it is unstable when heated and should not be used for cooking. Monounsaturated fatty acids are healthy because they lower cholesterol (see more on cholesterol below).
Polyunsaturated Fatty Acids: Includes the essential fatty acids omega 3 and omega 6. The health benefits of omega 3s have been well studied and have numerous positive effects on cardiovascular, neurological, mental and immune health. Cold water fish, whole grains, certain nuts (walnuts, pine nuts), seeds - including flaxseed oil, sunflower oil, and cottonseed oil as well as corn oil and other vegetables oils. Sadly, many cooking oils are in this group. Due to their chemical structure, polyunsaturated fatty acids are very unstable, becoming rancid when exposed to oxygen, heat, and light for too long a period. Cooking and processing with this type of oil leads to the formation of free radicals which results in inflammation and can lead to cancer, autoimmune diseases, neurodegenerative diseases, and premature aging.1 Never use polyunsaturated fatty acids for cooking or baking. Instead, they should be consumed in their natural state. Omega 3s like cold water fish and flaxseed can be cold pressed to produce their oils, but the oils must be stored properly. See last week's blog on essential fatty acids for more information.
What Makes Fat Bad
While some dietary fats are healthier than others, what generally makes them bad is how they are consumed and processed:
Consuming too much fat in general: Saturated fats should not make up the majority of your diet. Moreover, a diet high in fat is often also a diet rich in carbohydrates. Many of the bad, inflammation-producing fats (processed fats) are found in foods containing lots of carbohydrates. Moreover, research is now starting to show that it is the large amounts of bad carbohydrates (like processed carbohydrates which are typically low in fiber and, thus, cause a quick spike in your blood sugar which can lead to inflammation) and not the fat that is disease causing. Diets rich in bad carbohydrates cause inflammation which is associated with a myriad of serious health problems: heart disease, cancer, autoimmune disease, obesity, neurodegenerative diseases, and even high cholesterol. "The low-fat high-carbohydrate diet, promulgated by the National Cholesterol Education Program, the National Institutes of Health, the American Heart Association...and the Department of Agriculture food pyramid...may well have played an unintended role in the current epidemics of obesity, lipid abnormalities, type II diabetes and metabolic syndromes. This diet can no longer be defended by appeal to the authority of prestigious medical organizations or by rejecting a growing medical literature that the much-maligned low-carbohydrate high-protein diet may have a salutary effect on the epidemics in question." 4
Consuming improper proportions of essential fatty acids: Eating too much of foods high omega 6 fatty acids relative to the amount of omega 3s - which is the typical american diet - leads to inflammation which in turn leads to many serious health problems.
Cooking or baking with fats unsuited for heat: Monounsaturated fatty acids like olive oil are healthy when used properly - in a salad dressing or for low temperature cooking. Polyunsaturated fats should never be exposed to any heat.8
Processing: Processed oils like the many polyunsaturated vegetable oils you find in the supermarket are unhealthy because of the disease-causing free radicals which they contain. Trans fats (like Crisco) are polyunsaturated oils which have been hydrogenated to one degree or another to make them more stable and, thus, suitable for baking and cooking and to increase the shelf life of products which contain them. Thousands of commercial foods contain them from margarine and vegetable oils to breads, cookies, crackers, chips, and cake mixes. What may have seemed like a clever idea has ended up wreaking havoc with our bodies. Trans fats have now been implicated in cancer, heart disease, multiple sclerosis, and diverticulitis, among other diseases."1 Due to the detrimental health effects of trans fats, a 2012 article in the Journal of the American Medical Association stated that "consumption of trans-fatty acids (TFAs) adversely affects cardiovascular risk factors and is associated with increased risk of coronary heart disease (CHD) events, making the reduction of TFA intake key to achieving the Department of Health and Human Services' Million Hearts goal to reduce myocardial infarctions and associated medical costs. Effects of TFA intake include increases in low-density lipoprotein cholesterol levels and decreases in high-density lipoprotein cholesterol levels. Trans-fatty acids also have been associated with proinflammatory effects, endothelial dysfunction, and decreased insulin sensitivity in persons with insulin resistance."5 No amount of trans fat is safe to consume.1 Read the list of ingredients to make sure that none of the following ingredients are present before you buy that product: hydrogenated oil, partially hydrogenated oil, soybean oil, and canola oil.
The Reason for Cholesterol
Cholesterol has unfairly suffered from a bad reputation for a long time. The truth is that your body requires cholesterol to perform many vital processes from nerve conduction to hormone production to the protection of various organs including your brain from free radical damage. In fact 25% of the cholesterol in your body is found in your brain.3
Cholesterol is not fat, but rather a waxy substance produced in your liver and found in animal foods (meats, dairy products, poultry, eggs, game) and shellfish. When measuring the amount of cholesterol in your body, your health care practitioner usually runs a fasting lipid profile to check:
Total Cholesterol: Amount of HDL & LDL combined
High Density Lipo-protein (HDL): This is the healthy type of cholesterol.
Low Density Lipo-protein (LDL): The bad type of cholesterol which can cause heart disease.
Triglyceride: A type of fat that circulates in your blood stream and is stored in fat cells.
What's important to realize, however, is that the cholesterol consumed in your diet is not necessarily what raises your cholesterol level. This fact was alluded to in a report put out by the Framingham Heart Study:
"In undertaking the diet study at Framingham the primary interest was, of course, in the relation of diet to the development of coronary heart disease (CHD). It was felt, however, that any such relationship would be an indirect one, diet influencing serum cholesterol level and serum cholesterol level influencing the risk of CHD. However, no relationship could be discerned within the study cohort between food intake and serum cholesterol level." 6
Many studies have clarified this point and, thus, challenged the conventional wisdom regarding dietary cholesterol. "The perceived association between dietary cholesterol (DC) and risk for coronary heart disease (CHD) has resulted in recommendations of no more than 300 mg/d for healthy persons in the United States. These dietary recommendations proposed in the 1960s had little scientific evidence other than the known association between saturated fat and cholesterol and animal studies where cholesterol was fed in amounts far exceeding normal intakes. In contrast, European countries, Asian countries, and Canada do not have an upper limit for DC. Further, current epidemiologic data have clearly demonstrated that increasing concentrations of DC are not correlated with increased risk for CHD. ... More importantly, DC reduces circulating levels of small, dense LDL particles, a well-defined risk factor for CHD."7
The Take Home Message
Fats and cholesterol play an essential role in your health. When used properly and eaten in correct amounts, dietary fats are good for you. Eating large amounts of carbohydrates and consuming bad fats, however, can cause inflammation which has been linked to heart disease and many other illnesses, including diabetes. Dr. Donald Miller, as quoted in Dr. David Perlmutter's book, Grain Brain, puts it best when he said, "The sixty year reign of the low-fat, high carbohydrate diet will end. This will happen when the health-destroying effects of excess carbohydrates in the diet become more widely recognized and the health benefits of saturated fats are better appreciated."3
What matters with regard to fat is that you consume good fats in the right proportions and in a healthy manner. Your diet should also include lots of vegetables (an excellent source of good carbohydrates & fiber), fruits with lower sugar content like raspberries and apples, and other sources of good carbohydrates like legumes and whole, minimally processed grains (preferably organic)9. That means ordering the steak less often and a fish like salmon more often. It also means choosing a healthy helping of vegetables as a side and cutting out the fries completely. Depending on your age, state of health, and family health history (think genetic predisposition), the proper amount of fat versus carbohydrates in your diet may vary, but vegetables low in starch should make up the bulk of your meal. Furthermore, there is no one size fits all solution when it comes to proper nutrition and portion size. That's why it is so important to work with your healthcare practitioner to develop a nutrition plan that is tailored to best fit your profile. For more information or for a personalized consultation, contact us today.
1 McCaffrey, D. The Science of Skinny. DeCapo Press Boston 2012.
2 www.mercola.com The Cholesterol Myths That May Be Harming Your Health. October 2011.
3 Perlmutter, D. Grain Brain. Little, Brown and Company: New York 2013.
4 Weinberg, SL. "The Diet-Health Hypothesis: A Critique" The Journal of the American College of Cardiology. 2004; Vol. 33: 731-33.
5 Weitz, HD et al. Eliminating the Use of Partially Hydrogenated Oil in Food Production and Preparation JAMA. 2012;308(2):143-144.
6 Eades, MR. Framingham Follies. The Blog Of Michael Eades MD. September 2006.