The Big Fat Truth: 5 Benefits of a High-Fat Diet
Part of every new patient intake involves an in-depth dietary analysis. Great health begins in the gut, so we naturally spend a good portion of time during initial consults discussing my patient’s food choices and overall digestion. At least once a day I have a new patient sitting across from me in a visit proudly explaining that they’re already doing a great job with their food choices since they follow a low fat diet. This post is for you, my fat-phobic patients; an evidence-based guide to healthy fats (mostly for your benefit, partly for mine so I don’t have to spend as much of our precious intake time clearing up your misconceptions about fat).
Fats were falsely vilified as the primary cause of heart disease in the 1950s and 1960s with the publication of a series of studies spearheaded by a group of three Harvard researchers. Previously hidden sugar industry documents published in the Journal of the American Medical Association in 2016, showed that the Sugar Association paid these scientists $50,000 each to publish a biased review of research on sugar, fat and heart disease. These studies, published in the New England Journal of Medicine, minimized the link between sugar and heart health and instead blamed dietary fat for the rise in heart disease rates. As a result of this deception health officials have now spent decades encouraging North Americans to reduce their dietary fat intake and instead consume processed low-fat, high-sugar foods that many experts now blame for fueling the current obesity crisis. Nutrition dogma is hard to break, and it typically takes around 17 years for medical guidelines to match the best and most up-to-date research. Unfortunately, many medical doctors and dieticians are still teaching their patients to avoid dietary fats, even though the current research does not support this recommendation.
According to a recent survey, 9 out of 10 people are worried about consuming dietary fat. Most fat is healthy, satiating and a completely necessary part of our diets. Dietary fats from healthy whole foods provide essential fatty acids and fat-soluble vitamins. They are also the preferred fuel source for our brains, and research even shows that they can promote weight loss and helps us maintain a healthy body weight. Before we dive deeper into the benefits of a high-fat diet I feel it’s important to first differentiate between good and bad fats:
What is a good fat?
We have 3 main sources of dietary fats: trans, saturated and unsaturated. Unsaturated fats are a great choice to support optimal health and may even reduce your risk of heart disease. Polyunsaturated and monounsaturated fats, specifically those containing omega-3 fatty acids are particularly health-promoting. My favourite sources of unsaturated and healthy saturated fats include:
- Olives & Olive Oil
- Organic grass-fed meats
- Wild caught seafood
- Pumpkin seeds & pumpkin seed oil
- Coconut and coconut oil
Where do we find bad fats?
The one thing that all researchers agree on is that consuming trans fats leads to a list of poor health outcomes including diabetes, cancer, cardiovascular disease and even depression. Saturated fats in the form of processed foods have also been shown to increase your risk of heart attack (read more about the difference between “bad saturated fats” found in processed high-sugar foods and those found in natural sources like coconut in this fat-focused article). These are the top dietary sources of trans fats and saturated fats that should be avoided:
- Vegetable shortening
- Partially hydrogenated vegetable oils
- Canola oil
- Fried foods
- Processed foods: desserts, packaged baked goods, candies, pizza (sorry)
- Factory-farmed dairy products (organic cheese and milk fine for some people in moderation).
- Processed Deli meats
Now, the moment you’ve been scrolling for, the top 5 evidence-based benefits to eating a high-fat diet:
- People that eat a high-fat diet live longer: A study of over 100,000 participants found that those with the highest intake of dietary fat (35% of daily calories) were significantly less likely to get sick and die than those whose diets contained the lowest intake of fat (10% of daily calories). From these findings the authors’ concluded that “high carbohydrate intake was associated with higher risk of total mortality, whereas total fat and individual types of fat were related to lower total mortality.”
- A high-fat diet promotes weight loss: A meta-analysis (the gold-standard of great research) of 13 randomized control trials proved that those on high-fat low carb diets lost more weight and keep more off than low-fat dieters. Participants in these studies also reported decreased hunger and improved energy. This analysis also found that a low-fat diet can slow metabolism by around 400 kcal/day, while there was no significant decline in metabolism when eating a high-fat/low-carb diet.
- Healthy dietary fats improve cardiovascular health: unprocessed fats from olives and coconuts have been shown to lower ‘bad’ cholesterol (LDL) and raise ‘good’ cholesterol (HDL). A 2018 study comparing serum cholesterol levels from various dietary fats found that coconut oil and olive oil did not raise bad cholesterol levels. Coconut oil specifically was shown to even increase good cholesterol. The study concluded that butter and coconut oil/olive oils, which are all predominantly made up of saturated fats, have very different effects on your cholesterol levels. Furthermore, this study showed that the effects of dietary fats on cholesterol levels and health outcomes vary not just according to the classification of fats as saturated or unsaturated but according to the different profiles in individual fatty acids, processing methods as well as the foods in which they are consumed.
- Fat is protective against Alzheimer’s & memory loss: It’s estimated that around 50% of population will have neurodegenerative disease by the year 2030. Personally, I have a strong family history of Alzheimer’s disease and 1 genetic variant in the ApoE gene which predisposes me to developing a neurodegenerative disease. This susceptibility is the reason why I generally avoid carbohydrates and eat a diet rich in healthy brain-loving fats. Dietary fat composition is an important factor in blood brain barrier (BBB) function and blood cholesterol levels. Both Cholesterol and BBB function are involved in the development of Alzheimer’s disease, and the primary genetic risk factor for Alzheimer’s disease (APOE-ε4) determines how a person will transport and use cholesterol in the body. A qualitative review published in the Neurobiology of Aging Journal found an increased risk of dementia with consumption of trans fatty acids, and decreased risk with higher consumption of monounsaturated and polyunsaturated fatty acids.
- Fat gives you energy: ATP, aka adenosine triphosphate, is the source of energy in the human body. A large amount of ATP is generated from the digestion and synthesis of nutrients that we eat in our diets, and research shows us that dietary fat gives us more energy than dietary glucose (broken down from carbohydrates and sugars). Scientists have proven that fatty acid metabolism generates 22% more ATP than glucose metabolism, and all of my patients report that their energy is much better when they cut the carbs from their diet and instead fill up on healthy fats.
- Mensink, R.P et al. Effects of dietary fatty acids and carbohydrates on the ratio of serum total to HDL cholesterol and on serum lipids and apolipoproteins: a meta-analysis of 60 controlled trials. American Journal of Clinical Nutrition, 20134
- Khaw, et al. Randomized trial of coconut oil, olive oil or butter on blood lipids and other cardiovascular risk factors in healthy men and women. Nutrition and Metabolism. 2018
- Harcombe Z, et al. Evidence from randomized controlled trials did not support the introduction of dietary fat guidelines in 1977 and 1983: a systematic review and meta-analysis. Open Heart 2015.
- Dehghan M, et al. Associations of fats and carbohydrate intake with cardiovascular disease and mortality in 18 countries from five continents (PURE): a prospective cohort study. Lancet. 2017
- J.S. Volek. European Journal of Clinical Nutrition, 2013;789-96 / Westman E.C. American Journal of Clinical Nutrition, 2002;951-54