The Human Body Does Not Turn Sugar to Fat
The process of synthesizing fat from sugar is known as de novo lipogenesis—the new production of fat. This activity is highly efficient in some animals, such as pigs and cows—which can convert low-energy, inexpensive carbohydrates—grass, say, in the case of cows and grains for pigs—into calorie-dense fats.5 However, human beings are very inefficient at this process and as a result de novo lipogenesis does not occur under usual living conditions in people. Thus the common belief that sugar turns to fat is scientifically incorrect—and there is no disagreement about this fact among scientists or their scientific research.5-8
Under experimental laboratory conditions, however, where people are overfed large amounts of simple sugars, the human body will resort to converting a small amount of sugar into a small amount of fat (triglycerides) in the liver. For example, in one recent study, trim and obese women were overfed with 50% more calories than they usually ate—note, 535 of these extra calories each day came from four and a half ounces (135 grams) of refined sugar. In this forced-fed situation, the women produced less than 4 grams (36 calories) of fat daily from the extra carbohydrate.8 (So where does all that fat come from?—the fat you eat is the fat you wear.)https://www.drmcdougall.com/misc/2006nl/sept/sugar.htm
Sugar Does Not Cause Diabetes
After eating high-carbohydrate foods you might suspect that all that dietary sugar would cause the sugar in the blood to rise and this might lead to diabetes. That’s what many lay people believe. Even a few scientists have theorized that chronically elevated levels of sugar in the blood might wear out the insulin-producing cells of the pancreas and produce diabetes.11 Actually, this common thinking is incorrect—studies comparing sugar intake with risk of developing type-2 diabetes show people on high sugar diets are less likely to get diabetes.12 There is, however, a strong relationship between red meat consumption and diabetes.13
The lowest rates of diabetes in the world are found among populations that consume the most carbohydrate—for this reason type-2 diabetes is almost unknown in rural Asia, Africa, Mexico and Peru.14,15 However, when these people change to a diet rich in fats and low in carbohydrates they commonly become diabetic. Some of the highest rates of this disease (and associated obesity) are found in Hispanics, Native Americans, Polynesians, and Blacks who have recently adopted the American diet.16
Contrary to popular belief, refined sugars actually make the body’s insulin work more efficiently.17 When the refined sugar content of an experimental diet of people with mild diabetes was doubled from 45% sugar to 85% sugar, every measurement of their diabetic condition improved—fasting blood sugar, fasting insulin levels, and the oral glucose tolerance test all showed their diabetes was better.18 The researchers concluded, “These data suggest that the high carbohydrate diet increased the sensitivity of peripheral tissues to insulin.” The increase in insulin’s sensitivity (efficiency) exceeds any blood sugar-raising effect from consuming more carbohydrate.17 Because sugar does not cause type-2 diabetes, the American Diabetic Association has recommend “55% to 65% of a diabetic’s diet come from carbohydrate,” and sugary foods are allowed.19
The carbohydrates found in whole foods (starches, vegetables, and fruits) are much healthier to consume than refined sugars for a person wanting to prevent or cure type-2 diabetes for a variety of reasons—especially because of the adverse effects on weight gain and blood cholesterol and triglycerides of sugars compared to starches (more in next month’s newsletter). A high carbohydrate, vegan diet, has recently been shown to help diabetics stop medications and improve their overall health.20 (See my August 2006 newsletter)
Acceptable Sugar Use
The main reason sugar has a bad reputation is because of the company it keeps. People living in Western societies eat loads of rich foods that make them fat and sick. Along with their high intake of meat, dairy, and refined grains, they also eat a lot of simple sugars. In this caldron of malnutrition, sugar’s exact contribution becomes indistinct. But, in most people’s minds, sugar is the villain—the scapegoat, taking focus off the animal-foods and free fats (vegetable oils), which are much more of a burden to one’s health than simple sugar is. This misplaced emphasis results in a lost opportunity to regain lost health and appearance.
Sugar tastes great and can hugely enhance the enjoyment of eating. One practical point is that the addition of sugar will boost the acceptance of a low-fat diet, like the McDougall diet—increasing long-term compliance. However, to reap the greatest pleasure with the least harm, simple sugar should be put on the surface of the food where the tongue makes direct contact. This means sugars should not be added to the food during preparation—mixed up in the ingredients where the sweet flavors are hidden from the tongue’s taste buds. Using a small amount of sugar on the surface of the food is my recommendation for trim, healthy people. Meal frequency: There was a second paper published on these same subjects (which was a double cross over design, so a very well done study) and the found significant increases in total cholesterol, LDL cholesterol and in blood pressure, compared to when they ate more frequent meals. These findings were published in the April 2007 issue of the American Journal of Clinical Nutrition. However, remember, this was from one very large meal per day with the exact same calories as the more frequent meals.
This older study (3) found that "Although there was no difference in change of body weight by food restriction between the two groups, the decrease in lean body mass (LBM) was significantly greater in the 2M [meals per day] group than in the 6M [meals per day] group.
How do we lose fat when getting enough calories from carbs? Generally speaking, the human body is almost always burning fat. Under normal conditions, the body is burning about 50% of its energy from carbohydrates and about 50% from fat. Some say these may vary and range from 50-70% Muscle cells burn glucose from carbohydrate or fatty acids from fats. At rest, and during low activity levels, the human body is burning around 50/50 glucose and fat. The harder one works, the relative percentage of fuel from sugar goes up and the relative percent of fuel from fat goes down.
