Sugar is yummy. But we keep hearing that too much is bad for you.
From The New York Times:
So what’s the issue with added sugars?
It mainly comes down to the way they’re packaged.
Naturally occurring sugar is almost always found in foods that contain fiber, which slows the rate at which the sugar is digested and absorbed. (One exception to that rule is honey, which has no fiber.) Fiber also limits the amount of sugar you can consume in one sitting.
A medium apple contains about 19 grams of sugar and four grams of fiber, or roughly 20 percent of a day’s worth of fiber. Not many people would eat three apples at one time. But plenty of children and adults can drink a 16-ounce bottle of Pepsi, which has 55 grams of added sugar – roughly the amount in three medium apples – and no fiber. Fiber not only limits how much you can eat, but how quickly sugar leaves the intestine and reaches the liver, Dr. Stanhope said.
“You can’t easily eat that much sugar from fruit,” she said. “But nobody has any problem consuming a very high level of sugar from a beverage or from brownies and cookies.”
Why is it a problem to have too much sugar?
Many nutrition experts say that sugar in moderation is fine for most people. But in excess it can lead to metabolic problems beyond its effects on weight gain. The reason, studies suggest, is fructose. Any fructose you eat is sent straight to your liver, which specializes in turning it into droplets of fat called triglycerides.
“When you ingest fructose, almost all of it is metabolized by the liver, and the liver is very good at taking that fructose and converting it to fat,” said Dr. Mark Herman, an assistant professor of medicine at Harvard. Studies show a predictable response when people are asked to drink a sugary beverage: A rapid spike in the amount of triglycerides circulating in their bloodstreams. This also leads to a reduction in HDL cholesterol, the so-called good kind.
Over time, this combination – higher triglycerides and lower HDL – is one major reason sugar promotes heart disease, said Dr. Aseem Malhotra, a cardiologist and adviser to the United Kingdom’s national obesity forum. This sequence of events may even overshadow the effects of LDL cholesterol, the so-called bad kind.
“What many people don’t realize is that it’s triglycerides and HDL that are more predictive of cardiovascular disease than LDL cholesterol,” Dr. Malhotra said. “I’m not saying LDL isn’t important. But if there is a hierarchy, triglycerides and HDL are more important than LDL.”
Dr. Malhotra said that when people reduce their sugar intake, “their overall cholesterol profile improves.”
“I see this in so many of my patients,” he added. “The effects are rapid.”
How much sugar is too much?
One of the largest studies of added sugar consumption, which was led by the Centers for Disease Control and Prevention, found that adults who got more than 15 percent of their daily calories from added sugar had a higher risk of cardiovascular disease. For the average adult, that translates to about 300 calories, or 18 teaspoons of added sugar, daily. That may sound like a lot, but it’s actually quite easy to take in that much, or even more, without realizing it. A single 12-ounce can of Coca-Cola, for example, has almost 10 teaspoons of sugar; it can add up quickly.
The study found that most adults got more than 10 percent of their daily calories from added sugar, and that for 10 percent of people, more than 25 percent of their calories came from added sugar. The biggest sources for adults were soft drinks, fruit juices, desserts and candy.
While those might seem like obvious junk foods, Dr. Malhotra said, about half of the sugar Americans consume is “hidden” in less obvious places like salad dressings, bread, low-fat yogurt and ketchup. In fact, of the 600,000 food items for sale in America, about 80 percent contain added sugar.
Everyone’s tolerance for sugar is different. Studies show, for example, that people who are already obese may be more susceptible to metabolic harm from sugar than others. But Dr. Malhotra said that he generally advises people to follow the World Health Organization’s guidelines, which recommend that adults and children consume no more than about six teaspoons daily of added sugar.
“Could I tell you the exact limit where sugar starts to definitely impact cardiovascular health?” he said. “That’s difficult. But I think if people stick within the W.H.O. limits, then their risk is reduced.”