Obese people who have taken aspartame or saccharin in the last 24 hours had higher blood sugar rises after taking sugar than those who had not used artificial sweeteners (Applied Physiology, Nutrition, and Metabolism, May 24, 2016). Lead author Dr. Jennifer Kuk says, “Our study shows that individuals with obesity who consume artificial sweeteners, particularly aspartame, may have worse glucose management than those who don’t take sugar substitutes.” High blood sugar levels call out more insulin and high insulin levels lead to weight gain and inflammation, which increase risk for diabetes.
Virtually all scientists agree that North Americans need to reduce their intake of sugar. Sugared sodas and sugar-added processed foods are at least part of the cause of our epidemic of obesity, diabetes and heart attacks. The World Health Organization (WHO) recommends that sugar should be no more than 10 percent of total energy intake, and most North Americans exceed this guideline by a large amount. I believe that WHO should also recommend that people restrict artificially-sweetened drinks and foods. An article in the British Medical Journal (July 21, 2015) shows that artificial sweeteners are associated with increased risk for diabetes, even in people who are not overweight.
Possible Ways Artificial Sweeteners May Increase Risk for Diabetes and Weight Gain
Changing Gut Bacteria: Artificial sweeteners can change the bacteria in human colons to raise blood sugar levels (Cell Metab, Nov 4, 2014;20(5):701-3). One week of consuming artificial sweeteners changed the gut bacteria of apparently healthy humans to cause higher blood sugar levels after taking sugar. This study in humans confirms other studies in mice that showed artificial sweeteners may cause high blood sugar levels by changing the bacteria in the colon (Nature, Oct 9, 2014;514(7521):181-6).
Burning Fewer Calories: Researchers at Purdue University reported that rats that ate yogurt sweetened with saccharin consumed more calories, gained more weight, and were fatter than rats that ate yogurt sweetened with sugar (Behavioral Neuroscience, Feb 2008;122(1)). The saccharin-fed rats did not lose the extra weight that they put on after they stopped eating the saccharin. You store extra fat when you take in more calories than you burn. These researchers suggest that the rats who were kept on saccharin had a smaller rise in body temperature after eating than those who were fed sugar, and therefore they burned fewer calories.
Taking in More Calories: PET scan evidence suggests that taking artificial sweeteners stimulates the brain’s pleasure centers, causing you to want to eat more. However, since you don’t get extra calories in artificially sweetened foods and drinks, you have to get them from somewhere else, so you eat more food (Trends in Endocrinology & Metabolism, July 10, 2013).
The only possible benefit of artificial sweeteners is that they may get some people to take in less sugar. Water is the safest drink, and unsweetened coffee and tea also appear to be safe. More than 40 percent of North Americans today have higher than normal blood sugar levels, so I believe that everyone should avoid any type of sugared drinks, except during prolonged exercise. Artificial sweeteners are associated with weight gain, and even small amounts of weight gain increase your risk for diabetes. Artificial sweeteners affect gut bacteria in ways we do not yet fully understand, but I believe this is sufficient reason to limit or avoid them.