The Truth About Saturated Fats & the U.S. Dietary Guidelines

October 15, 2019

Saturated fat, the kind of fat found in animal products like meat and dairy, is one of the most hotly debated topics in the nutrition world. I stumbled across a fabulous podcast this week on this topic and the guest speaker, Zoë Harcombe, who has her PhD in Public Health & Nutrition, was so impressive that I thought I'd detail some of her finer points here.

Ms. Harcombe recently published a paper (and wrote her PhD thesis) critiquing the U.S. and the U.K. Dietary Guidelines for their lack of evidence behind the recommendations listed in those guidelines, one of which is to limit saturated fat to 10% of calories. There is way too much information to go into here, but it all began after an analysis of 6 famous studies -- 5 of which actually found no issue at all with dietary fat.

Ms. Harcombe admits to beginning her years of analysis on the studies that were the basis for our dietary guidelines with a slight bias -- as a vegetarian herself, she expected to find that saturated fat SHOULD be limited in the diet. But what she found was the opposite. In fact, one study even went as far as to say that, "A low fat diet has no place in the treatment of myocardial infarction (heart attacks)."

Here are my favorite tidbits from the podcast:

1. Humans need to consume fat. Essential fatty acids earned their name because they are *essential* for our survival. The fat-soluble vitamins A, D, E and K come in foods that contain fat and they need fat to be absorbed. We would die without them.

2. Almost every food contains fat (except sucrose). And every single food that contains fat contains all 3 types of fat -- saturated fat, monounsaturated fat and polyunsaturated fat. Only the proportions vary.

3. Ms. Harcombe shows the benefits of saturated fat in her research but even if it WAS the worst type of fat to consume, as it is touted to be, there would still be no reason to avoid animal products. Animal meat actually contains more UNsaturated fat than saturated -- with its highest proportion being monounsaturated fat. For example, lard, which is largely maligned, is 39% saturated fat -- while coconut oil (widely accepted as healthy) is 97%.

4. Mackerel has twice the total fat and 1.5x the saturated fat as a sirloin steak. One tablespoon of olive oil has more saturated fat than a 100 gram pork chop! So why -- if saturated fat is so bad for us -- are we are typically told to eat tons of fish and olive oil and to avoid steak and pork chops? It doesn't make any sense.

5. The U.S. dietary guidelines say to restrict total fat to 30% (and saturated fat to 10%) of calories. As protein is in almost every food (except sucrose & oils) and tends to stay pretty constant at around 15% of calories for most people, the guidelines telling us to restrict our fat intake automatically causes carbohydrate intake to fall at around 55%. So that's more than half of our calories from the one macronutrient we don't actually NEED to survive.

Homo sapiens has been around for 2-3+ million years living on whatever we could forage and hunt so why have we decided, in the last 40 years, that that's bad?!? I will leave you with my favorite quote from Zoë Harcombe: "Whether your belief system is in God or nature -- food is provided around us on this planet and it makes no sense that, in that same food that we need to thrive and survive, something has been put that is trying to kill us."