Artificial sweetener use is a complicated topic, says Dr. Rekha Kumar, an endocrinologist at NewYork-Presbyterian/Weill Cornell Medical Center, because “we’re learning of the health consequences of artificial sweeteners after the population has practically become addicted.”
Health Matters spoke with Dr. Kumar about the pros and cons of popular sweeteners, and how to weigh the risks and benefits of using them.
Let’s start with sugar. What happens when you eat too much sugar?
Dr. Kumar: Sugar is the most fundamental form of a carbohydrate, and carbohydrates are a category of macronutrients that are essentially the building blocks for energy. Sugar is the easiest way for humans to get the energy we need to think, move, and complete metabolic processes.
Consuming too much sugar has only become an issue in the last 40 to 50 years, with the rise of the obesity and diabetes epidemics. Prior to COVID, metabolic disease, excess sugar, and excess calories —which all lead to diabetes — were thought to be the biggest public health problems.
Basically, when you have too much sugar, you’re storing more calories than you’re burning. Ideally, when sugar or carbohydrates are used for energy, you’d expend energy in some way — let’s say by labor-intensive work or intentionally exercising. But today, most people can’t exercise off the amount of sugar that has become typical of the American diet.
Are all sugars created equal?
No, not all carbohydrates, of which sugar is the simplest form, are created equal. For example, complex carbohydrates like starch, which are found in whole grains and starchy vegetables like carrots and beans, can be very healthy. Foods like fruit, which have naturally occurring sugars, are also full of vitamins, minerals, and fiber. So although you’re ingesting sugar, you’ll eventually get full and stop eating, which is not the case when you eat candy and drink soda.
What are the pros and cons of artificial sweeteners?
Artificial sweeteners were developed to create sweetness without adding calories or spiking blood sugar in patients with diabetes. They were likely meant to be used in very small quantities, but they have been used in excess. And in excess there can be harm.
We’re starting to learn that they may increase risk of cancer and DNA damage by altering the microbiome. But artificial sweeteners are also so much sweeter — 200 to 600 times sweeter, depending on the type — than actual sugar. And as a result, people crave foods that are of the same sweetness.
What is an appropriate amount of sugar for someone to consume in a day?
I tell my patients as little as possible. But according to the American Heart Association, men should consume no more than 9 teaspoons of sugar a day, and women should consume no more than 6 teaspoons.
What’s an appropriate amount for artificial sweeteners? And what are the health concerns if you consume too much?
Based on the growing body of literature showing that artificial sweeteners could cause DNA damage and increase the risk of cancer, I would recommend consuming as little as possible. That said, so many people in the U.S. are being treated for chronic conditions, like diabetes and heart disease, that are much more likely to shorten their lifespan than an artificial sweetener would.
People with diabetes are probably safer consuming non-nutritive sweeteners or sugar substitutes, because they’re at a higher risk for complications and long-term morbidity if their sugar intake is too high. But we have to weigh each person’s risks and benefits, age and stage of life, and medical conditions to determine whether sweeteners or real sugar is better for them.
For an active child without diabetes, in my opinion we wouldn’t want them ingesting chemicals that could potentially alter their DNA because they have a whole life ahead of them. It’s a different story for an 80-year-old with diabetes; they’re more likely to die of uncontrolled diabetes than cancer caused by a sweetener.
Sucralose, which is in Splenda, is an option for people who want to control their blood sugar. But sucralose is actually difficult to digest because it’s a sugar alcohol. Sugar alcohols alter the sugar molecule in a way that makes it more difficult to absorb, which causes many people to experience bloating, diarrhea, and an upset stomach. As a result, increased usage of these types of sweeteners causes a lot of people to develop irritable bowel syndrome.
For the average healthy person, I wouldn’t recommend aspartame. From my experience, I’ve noticed that patients who drink diet sodas often drink many a day. We’re not quite sure why, but people seem to get addicted to that flavor profile and crave the sweetness. In that way, a healthy person could still be at increased risk of diabetes because their brain is starting to crave sweeter things.
What about natural sugars and sweeteners? Are they better for you?
Although honey and agave are different forms of natural sugar, they should still be used in moderation. Agave is higher in fructose and has a greater ability to cause metabolic disease than plain sugar. And honey is very calorically dense. Because of the obesity epidemic, I can’t say that I favor honey over table sugar.
Natural sweeteners like stevia or monk fruit sweeteners might be better alternatives to chemical sweeteners, especially for younger people, whose longevity makes the risk of DNA damage very real. And while there isn’t conclusive evidence of this, the fact that natural sweeteners are derived from plants probably means there are fewer long-term health risks.
But they’re still significantly sweeter than real sugar: Stevia sweetener is 200 to 350 times sweeter than sugar, and monk fruit sweetener is 100 to 250 times sweeter. So while they aren’t artificial, they could still contribute to chronic disease by impacting flavor profiles, which puts people at risk of diabetes. You still have to use them in moderation.
What do you tell people who are trying to cut back on sugar and want healthy alternatives?
I recommend balancing natural sugars, like fruit, with a fat or protein; an apple with peanut butter or cheese is a great example. It provides you with the satisfaction of sweetness, but the fat and protein signal fullness to the brain. If you only eat sugar, whether it’s in a natural form or artificial form, you don’t feel full, which creates the vicious cycle of wanting more sugar.
Overall, I recommend skipping the diet drinks altogether and having water instead. I don’t think diet drinks are good in any form. If taste is an issue, I suggest trying flavored seltzer, water with a slice of lemon, or even milk.
Rekha B. Kumar, M.D., is an attending endocrinologist at NewYork-Presbyterian/Weill Cornell Medical Center and an associate professor of medicine at Weill Cornell Medicine. She specializes in the diagnosis and treatment of various endocrinology disorders, including obesity/weight management and thyroid disorders. She is also the former medical director of the American Board of Obesity Medicine.