Should Keto Dieters Also Limit Saturated Fat Intake?
Limiting your intake of saturated fat is one of the golden rules of nutrition. But if up to 80% of your diet is coming from fat while following a keto eating plan, do you need to worry about saturated fat like the general population? Here’s what the research says…
Roughly a decade ago, a meta-analysis of over 70 studies found no evidence that eating saturated fat causes heart disease. And since then, other studies have reached similar conclusions. These recent studies on the association between saturated fat and heart disease—or lack thereof—ran contrary to what health experts told the masses since the mid-20th century.
Is that the end of the story if you’re following a low-carb lifestyle? Should you go load up your dinner plate with steak, butter and cheese?
Hold on to your plate because the experts that had warned us over the last approximately 60 years that saturated fat might cause serious health problems may have been right. Albeit for the wrong reason.
Whether saturated fat causes heart disease is up for debate. Many studies fail to control for various factors. For example, what is the quality of the meat? Was it 100% grass fed beef raised on a regenerative farm? Or did the subjects consume lots of processed meat with advanced glycation end products (free radicals that cause premature aging)? Did the subjects exercise and lead generally-healthy lives or did they lead sedentary lives, snack often and drink lots of alcohol?
Nonetheless, mainstream health organizations such as the American Heart Association refuse to budge from their stance that diets high in saturated fat cause cardiovascular problems. Meanwhile, independent natural health influencers believe that it’s not so much saturated fat that leads to heart disease, it’s oxidized saturated fat or any type of fat that becomes oxidized (most often through exposure to high heat and light). So the debate rages on…
But let’s suppose every single study on saturated fat was administered by giving extremely-fit subjects the healthiest omega-3-rich meat. Even if this were the case, you may still want to take it easy on foods that are high in saturated fat. The reason why is indirectly related to cardiovascular health. But primarily, it’s because saturated fat “significantly worsens insulin resistance,” according to a research review published in Clinical Nutrition.
Saturated Fat & Insulin Resistance
Although the research article is nearly two decades old, it brings up an important aspect that rarely gets any attention in mainstream nutrition. It may seem counterintuitive that any type of fat—be it monounsaturated, polyunsaturated or saturated—can spike insulin levels. After all, fat doesn’t contain any sugar and only a tiny fraction of a fat molecule can be used by the body as glucose.
You may be familiar with the concept of gluconeogenesis, in which the body can make glucose from protein if not enough ketone bodies are present or if you eat a meal with a very large serving of protein (like a 72-ounce porterhouse steak).
But insulin resistance from saturated fat? How is that even possible?
For starters, eating a large amount of saturated fat can delay the time it takes for glucose to enter the cells. But if you’re eating a very tiny amount of carbs to begin with because you’re keto does this matter? Probably not as much as the average eater, especially if you’re already healthy. Healthier people don’t experience as much insulin resistance from saturated fat as overweight/obese subjects. But it’s worth keeping this concept in mind.
In fact, a study in the European Journal of Nutrition on overweight or obese people administered a subset of subjects a diet consisting of 55% fat. Not exactly keto, but it’s high-fat in comparison to the average diet. The researchers reached the same conclusion as the Clinical Nutrition study above. Diets high in saturated fat adversely affects insulin sensitivity, which places one at a higher risk of developing type 2 diabetes.
Does Insulin Go Up After A High-Fat Meal?Interestingly, eating a high-fat meal does not raise insulin levels in the short-term. The greater concern is the long-term effect. And the research suggests saturated fat more so than monounsaturated creates insulin resistance over time.But a 2020 study published in Nutrition & Diabetes reached a radically different conclusion, suggesting that a ketogenic diet not only has a therapeutic effect on glycemic and lipid control among patients with type 2 diabetes but also significantly contributes to their weight loss.
Well, the only way to know for sure is to do what you do if you’re on keto: test, test, test. Keep testing not only your ketone body levels but also your fasting blood sugar and A1C levels as well. Because everybody is biochemically different, some keto dieters may not need to worry about saturated fat intake while others might need to adjust their diet down the line.
So which is it? Does a high-fat diet, specifically one rich with saturated fat cause the body to need more insulin in order to control blood sugar?
Genetics And Insulin Resistance
And as a side note, keep in mind that some people have a genetic disposition (mutations of the PPARG gene) that causes a decrease in the fat-burning potential of adipocytes (fat cells). This places one at a higher risk of insulin resistance and type 2 diabetes.
The bottom line is that eating more healthy fats and less blood-sugar spiking and insulin-releasing carbohydrates makes sense for everybody. For most people, it can’t hurt to consume more avocados, avocado oil, olives, olive oil, nuts and seeds and less red meat and dairy.