The recent prevailing mood regarding sugar swings between worry that it's not particularly good for you, to conviction that it's downright poison.
There's no doubt that sugar makes food more appealing -- some say even craveable and addictive -- and that a sugar-amplified diet has a role in overeating and obesity. But what several researchers are finding is that regardless of weight gain, regardless of caloric intake, sugar -- especially fructose -- in excess is detrimental to health.
A rigorous new study in Obesity, led by Robert Lustig, shows that reducing overconsumption of fructose is metabolically beneficial in and of itself.
The study involved 43 obese 8- to 18-year-olds, all of whom were heavy sugar consumers (28 percent of their diet was added sugar!) and also had at least one metabolic risk factor, such as high blood pressure, glucose intolerance or high triglycerides.
For nine days this group ate an added-sugar restricted diet, while still aiming to maintain the same amount of total carbohydrates and calories.
Short explainer about sugar, fructose and glucose; I promise it's short and necessary in order to understand what this experiment teaches. Foods and drinks are usually sweetened with sugars that are a combination of the simple sugars glucose and fructose. Sucrose (table sugar) is a two-sugar molecule with 1 glucose and 1 fructose bound together, and is therefore exactly 50 percent glucose, 50 percent fructose. High Fructose Corn Syrup (HFCS) is about 45 percent glucose, 55 percent fructose. Practically all forms of caloric sweeteners used in food processing are glucose/fructose mixes. So how does one maintain the sugar level while reducing fructose? The answer is starches, which are pure glucose chains.
The study didn't change the kids' diet to a kale, hemp seed and quinoa retreat, but rather just replaced foods with lots of added sugars with other processed foods such turkey hot dogs, pizza and baked potato chips, that have little or no added sugar, and instead contain carbs in the form of starches.
Just 10 days later there were significant metabolic improvements: Glucose tolerance, blood lipids and other markers of liver health changed for the better.
As mentioned before, the study aimed to keep caloric intake steady, and for the kids' weight to stay the same. However, despite the effort, and even though the researches even added calories to that effect, the kids lost about 1 kg on average (2.2 pounds) in the nine-day study. Could this mild weight loss explain these metabolic improvements? The researchers performed regression analysis and claim it's unlikely -- I won't go into that complicated explanation.
So, is sugar toxic?
This study is further proof that reducing added sugar to more reasonable amounts benefits kids at risk of metabolic syndrome and diabetes.
Dr. Lustig often warns about the dangers of fructose, emphasizing that glucose isn't the problem. In practicality, since added sugars are almost always at least 50 percent fructose, the sensible advice it to cut all added sugar.
Sugar in large amounts is definitely associated with weight gain, and likely also independently with diabetes and metabolic and heart disease. Reducing it (even without intentional caloric restriction) usually leads to weight reduction, and to improved health outcomes.
So cutting on added sugar and aiming for the World Health Organization's and the American Heart association's target of no more than 6 teaspoons a day for women, 9 teaspoons a day for men, is very sound advice. The first step towards that not-easy-to-achieve goal is to know how much sugar is added to our food, which is what's proposed by the FDA, and fought mightily by the food industry.