How Much Sugar Is Safe?

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  • Recall when former New York City Mayor Michael Bloomberg tried to ban the sale of sugary drinks larger than 16 ounces? It started the "Big Gulp" rebellion, even though the ban was overturned in the courts.

    The truth is that too much sugar is making America fat, but how much is too much? Well, less sugar than you'd think if a new finding in mice is also true of people.

    In the study, a quarter of the calories fed to one group of mice came from sugar-mimicking high fructose corn syrup, which in human terms equals about three cans of sugary drinks a day. That describes the consumption of a quarter of the U.S. population.

    The sugar-fed mice and the mice on a normal diet stayed on those diets for 26 weeks. Then they were all released into a natural environment together - and the results were stunning.

    Over the next 32 weeks, the sugar-fed mice had a two-fold increase in death rate compared to the control group. And the sugar-fed mice produced a quarter less offspring and held a quarter less territory than male mice fed the normal diet.

    These mice showed minor physiological differences such as increased cholesterol levels, but what's significant is how this diet produced such major life outcomes. The sugar-fed mice had a shorter lifespan and lower reproductive and competitive success.

    We may see similar studies in the future as scientists look for overall changes in quality of life even when they don't find clear physiological changes. A new nutrition guideline could be in our future, especially when you consider that more than a third of us are obese. Looks like former Mayor Bloomberg was on to something after all!

More Information

Human-relevant levels of added sugar consumption increase female mortality and lower male fitness in mice
Original Nature Communications article by Ruff et al. from University of Utah.

"Safe" levels of sugar harmful to mice
Article by Brian Owens describing the mouse study by Ruff et al.

Dietary Guidelines for Americans
Guidelines published by the USDA and the U.S. Department of Health and Human Services.