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What are added sugars doing to your body?
Added sugars are ubiquitous on American grocery store shelves. Sugar boosts flavor, color and texture in foods, can help preserve jams and jellies, acts as a bulking agent in baked goods, and balances the acidity in foods and condiments containing vinegar and tomatoes.
However, added sugars also contribute extra calories in exchange for little nutritional value, and can lead to a variety of health problems including weight gain, tooth decay and increased triglycerides, which increase the risk for heart disease.
A study, scheduled to be published in the February 2016 issue of the journal Obesity, found that reducing the amount of added sugars in a diet can reverse several chronic metabolic diseases, including high cholesterol and high blood pressure, even without reducing the total amount of calories consumed.
Lead researchers Robert Lustig, MD, MSL, a pediatric endocrinologist at the University of California San Francisco Benioff Children’s Hospital, spoke to Endocrine Today about added sugars and their effect on the body.
ET: What kinds of foods contain added sugars, and how prevalent are they in the food most people buy?
RL: Well, first of all, they are in everything. Second of all, 74% of all the items in the American grocery store are spiked with added sugar on purpose by the food industry – for their purposes, not for yours. This is their hook, their way of getting you to buy more. They know the more they add, the more consumers will buy.
Sugar is in all the things you’d expect it to be in – candy, cake, ice cream – obviously anything that’s confectionary. But the things that are not obvious are the things like yogurt, salad dressing, barbecue sauce, tomato paste and ketchup; pretty much anything that adds any acidity will have sugar added to it, to basically cover up the acidity. They even add it to meats. If you’re eating processed food, you can’t escape it.
ET: What doesn’t contain added sugar?
RL: It’s not in real food – food that doesn’t have a label. If it has a label, it’s been processed, and if it’s been processed, it has sugar added to it, and likely had fiber removed from it. That’s part of what makes it processed. Pretty much anything that has a logo that you’ve heard of is processed, and that means it has had sugar added to it.
ET: How does it affect the body?
RL: Each of us has a capacity to metabolize sugar, but we have a limited capacity to metabolize. Take alcohol for example – will one drink hurt you? No. Will two drinks hurt you? Probably not. Will three drinks hurt you? Well, you’re getting there. Will four hurt you? Most people, yeah. And five drinks? And you’re on the floor. Same thing with sugar.
If you keep your consumption down to a rational amount, then your liver has the capacity to metabolize and it’s unlikely to cause negative effects. If you consume a lot, which is what our children are doing, particularly when they consume soda and juice, what happens is your liver’s capacity to metabolize the sugar is overwhelmed and the liver has no choice but to take the excess that it can’t metabolize, and turns it into fat. Now you’ve got fat in your liver.
Our data has shown that fat in your liver has either one of two fates. It will either get exported out of your liver as triglyceride, which poses a danger of heart disease and obesity, or it will stay in the liver, which can develop into fatty liver disease, and cause all the other chronic metabolic diseases, such as diabetes, cancer, dementia and hypertension.
ET: What is the difference between added sugars and natural sugars, like those found in fruit?
RL: Fruit is OK because, even though fruit has naturally-occurring sugar, fruit has fiber and lots of it. And there’s way more fiber than there is sugar. Fiber has three effects that make the sugar in the fruit OK. The fiber acts as a gel on the inside of the intestine that reduces the rate of absorption of sugar from the gut into the bloodstream, so your liver doesn’t receive it all at once.
In addition, some of the sugar won’t even be absorbed, and it goes further down the intestine, where the bacteria will chew it up, and that’s called the intestinal microbiome, and the more energy that goes to the intestinal microbiome, the more bacterial diversity you can have, which is actually good for holding off the bad bacteria and keeping them at bay, and improving your health. And lastly, the fiber moves through the intestine so much faster, that you get the satiety signal at the end of the intestine sooner, so that you don’t overconsume.
It’s not that the sugar in fruit is any less bad for you. If you extracted that sugar out of that fruit and purified it, it would be the same sugar as you would find in the 5 lb. bag in the grocery store, but it comes with the fiber.
ET: What advice would you give to consumer who are reading nutrition labels and trying to limit the amount of added sugars in their diet?
RL: Remember that there are 56 names for sugar so labels won’t always say ‘sugar’. It may say cane juice, or high-fructose corn syrup, or maltose or dextrose. There’s pretty much a carte blanche. The food industry uses all of them because the food labels have to list all the different ingredients by math; if you use a different sugar as number 5, and number 6, and number 7, number 8 and number 9, and when you add it up, it can be number 1. So, it can hide in plain sight.
ET: What can physicians do to be more proactive in helping patients improve their diet?
RL: The first thing we’ve learned from all of our studies is that the standard mantra – “If you fix the obesity, the metabolic dysfunction will improve” – is wrong. Rather, it’s the opposite. If you fix the metabolic dysfunction, the obesity will improve. What we have found is if you get the insulin down, you stop shunting energy to fat, your brain starts being able to see the satiety signals, you of your own volition reduce your total consumption, you increase your exercise capacity because you feel like it, because you’re not trying to conserve anymore, you’re trying to burn, and you can lose weight.
You have to get the insulin down, and to do that you have to fix the insulin resistance. Well, what caused the insulin resistance? The liver fat. And what caused the liver fat? The sugar. The first thing and the primary tenant of any obesity management is get rid of the added sugar in the patient’s diet as priority one. If you don’t do that, nothing else will work.
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