Walking through the grocery store, one can’t help but see the campaign against fat: low-fat yogurt, fat-free salad dressing and skim milk all play their roles. There are even fake-fat potato chips out there. From fat burners to fat blockers, it seems like fat, and especially saturated fat, is Public Enemy #1.
Most anti-fat crusaders state that it is not the monounsaturated or polyunsaturated fat that is the problem; rather, the fault lies with our consumption of saturated fat. They consistently recommend eating foods that are high in the unsaturated fats, such as fish and olive oil, and avoiding saturated fat-laden foods like butter, pork, lard and coconut oil. While they may even agree that all fats are healthy, they also recommend that such “healthy” fats should constitute no more than 7–11% of our total calorie intake.
However, what is the real story behind saturated and other fat? Is fat really the weight-enhancing, heart disease-inducing, artery-clogging, cancer-causing, acne-generating villain we make it out to be? Will it ruin your health? Frankly, is fat really bad for you?
Several years ago, Westman et al. published an interesting report in The American Journal of Clinical Nutrition. In this report, the researchers performed a meta-analysis of several published papers wherein subjects had their caloric intake derived from either a carbohydrate majority and a fat minority or a fat majority and a carbohydrate minority. Protein was also included in the mix. In some studies, subjects derived as much as 89% of their daily energy requirements from fat.
What happened to the study subjects who lived primarily on fat? Amazingly, as opposed to their carbohydrate-munching cohorts, the “fat” subjects not only experienced a drop in their LDL cholesterol and total triglyceride levels but a rise in their HDL cholesterol (the so-called “good” cholesterol). Diabetic subjects underwent a drop in their endogenous glucose production and an improvement in insulin-stimulated glucose disposal, both of which are signs of a stabilized glucose metabolism. As far as weight loss itself was concerned, high fat as well as high carbohydrate diet subjects felt the same levels of hunger, yet only the high fat diet subjects ate up to 1,000 fewer Calories per day than their bread and pasta-munching cohorts.
More and more researchers and nutritionists are stating that fat should constitute a generous portion of our daily caloric intake not only for maintaining optimal health and ideal weight, but also for defending against what is increasingly being called “metabolic syndrome.” According to the American Heart Association and the National Heart, Lung and Blood Institute at NIH, metabolic syndrome consists of increased risks for cardiovascular disease, stroke, diabetes and inappropriate immune response (including allergy and arthritis). Metabolic syndrome can be physically recognized by having excess weight around the midsection (i.e., having the so-called “apple” shape), elevated systolic and (especially) diastolic blood pressure, high LDL cholesterol and triglycerides and high fasting blood glucose. Interestingly, when such individuals who suffered from metabolic syndrome were placed on a high-fat diet by University of Connecticut researchers, their LDL cholesterol levels dropped, HDL/LDL ratios improved and triglyceride levels plummeted. Baseline immune response was reduced, indicating a reduction in inflammation. Incidentally, this high-fat diet group also lost weight.
Prior to the Agricultural Revolution of roughly10,000 years ago, humans primarily hunted and gathered their food. As opposed to being in large and permanently settled communities that relied on cereal crops, hunter/gatherer humans subsisted on fish, land animal meat, plants and berries. Such food sources had to be tracked far and wide before they could be adequately obtained; thus, the humans of the pre-Agrarian Age were mostly nomads and set up only temporary housing at best.
With the domestication of grasses such as corn, rice and wheat, large communal societies became possible. One of the advantages of living in a settled society with a reliable food source was that one could now do other things besides just hunt/gather; the fields of philosophy, politics, art and science flourished. Unfortunately, one of the disadvantages of living in a settled society was that one now subsisted on an entirely unknown and unproven food source.
According to some proponents of what is popularly called The Paleolithic Diet, humans survived for 100,000+ years by hunting and gathering their food. By some accounts, our genus Homo survived as long as 2.5 million years through hunting and gathering food. In comparison, we have spent only the last 10% of our own species’ existence as agriculturalists. As a result of this sudden shift in our food source, a food source to which our bodies did not evolve, we may be paying the price today with metabolic syndrome.
Proponents of the Atkins Diet also argue that a low-carb and high-fat/protein diet is the way towards health and weight loss. They state that our carbohydrate-laden diets predispose us towards diseases like diabetes because they trigger constant insulin production and release. In the presence of insulin, glucose is stored rather than burned up, leading to weight gain. Furthermore, various grain components, such as gluten, trigger the body’s immune response, leading to autoimmune reactions (such as celiac disease), heart disease, rheumatoid arthritis and diabetes.
Regardless of whether you agree with the tenets of the Paleolithic and/or Atkins diets, there is no doubt that a significant portion of our bodies are made up of fat, including saturated fat. The human brain, for example, is composed mostly of fat and cholesterol, and most of that fat is actually saturated fat. In terms of the skeleton, calcium is more readily absorbed into bones when the person is ingesting a high fat diet composed of at least 50% saturated fat. Immune functions are significantly improved by the presence of saturated fatty acids like myristic acid and lauric acid, especially lymphocyte recognition of infection. And in terms of the heart, it is the saturated fatty acids like stearic acid and palmitic acid that the heart draws on for energy in times of stress.
Thus, it would appear that a high fat diet that is heavily weighed towards saturated fat may in fact be good for you. Our exclusion of unsaturated as well as saturated fatty acids from our diet may be hurting us more than we realize; heart disease, the most widely touted effect of a high-fat diet, may indeed be on the rise as a result of our low-fat lifestyle. In contrast, the Inuit people of Greenland or the Massai of Kenya and Tanzania, both of whom live on high animal fat diets, also both have low incidences of cardiovascular disease.
Fat has long been maligned as a major health villain and its true role in health and disease is only now starting to be realized. While most of us would prefer not to live on an all-whale blubber or lard diet, many of us would also not suffer from enjoying a glass of whole milk, some scrambled eggs and bacon for breakfast. Alternately, we might try eating a few whole avocados while frying up some vegetables in coconut oil. And as far as lard is concerned, this current bane of the medical profession may in fact emerge as our newest health food.
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Boden et al., Effect of a Low-Carbohydrate Diet on Appetite, Blood Glucose Levels, and Insulin Resistance in Obese Patients with Type 2 Diabetes. March 15, 2005 vol. 142 no. 6 403-411.
Grundy et al., Diagnosis and management of the metabolic syndrome. An American Heart Association/National Heart, Lung, and Blood Institute Scientific Statement. Executive summary. Cardiol Rev. 2005 Nov-Dec;13(6):322-7.
Volek et al., Effects of dietary carbohydrate restriction versus low-fat diet on flow-mediated dilation. Metabolism. 2009 Dec;58(12):1769-77. Epub 2009 Jul 25.
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