July 17, 2023

Do You Need To Cut Out Aspartame?

Moderation is important for lowering risks

Closeup of sugar substitute in granulated and pill form on a blue background.

Some things are well-understood to be healthy for our bodies: fruits, vegetables, exercise.


Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy

And some things are almost universally agreed as a danger to your well-being: smoking, drug use, driving without a seatbelt.

But not everything is so clear-cut. Not every food we eat or activity we do can fall neatly into the category of “good for you” or “bad for you.” There are gray areas. Questions of quantity. Matters of how you personally react to one thing or another.

That’s the case with the artificial sweetener aspartame.

On one hand, aspartame can be a saving grace for people with diabetes (“Sweet taste without the calories, and no impact on your blood sugar!”). On the other, there’s reason to be cautious.

Amid reports declaring aspartame a possible carcinogen (cancer-causing agent), we talked with oncologist Dale Shepard, MD, PhD, about aspartame — the good, the bad and what to do about it.

What is aspartame?

Aspartame is an artificial sweetener that goes by brand names like NutraSweet®, Equal® and Sugar Twin®.

Like other artificial sweeteners — including saccharine (Sweet’n Low®) and sucralose (Splenda®) — it’s a common ingredient in foods labeled “sugar-free” or “no added sugar.” That can include products like:

Aspartame and other non-nutritive sweeteners are popular among people looking for a sugarless route to satisfying their sweet tooth. That includes people with diabetes, people on sugar-restricting diets like keto and people who are trying to lose weight.

A gram of aspartame contains 4 calories, which is the same as sugar. But aspartame is 200 times sweeter than sugar. So, you don’t have to use nearly as much to get the same sweetness factor.

So, if you switch from sugar to aspartame, you essentially cut the calories to zero. And aspartame doesn’t impact your blood sugar, so it’s marketed as a good choice for people with diabetes and other people who need to be monitor their blood sugar.

Does aspartame cause cancer?

The latest scientific evidence suggests that aspartame may be associated with cancer. And the World Health Organization (WHO) lists aspartame as a possible cause of cancer. None of that means that aspartame directly causes cancer. There’s a difference.


Let’s look at the research.

In the largest trial to date on the effects of aspartame, researchers followed more than 100,000 people over about eight years and documented what they ate and drank. They found that people who consumed aspartame at high levels were about 15% more likely to develop cancer than people who didn’t have aspartame in their diet. That included an increased risk of:

  • Breast cancer.
  • Endometrial cancer.
  • Colon cancer.
  • Stomach cancer.
  • Prostate cancer.

“When we research foods and their connection to cancer, we can see when people who eat a particular type of food are more likely to develop cancer, but that’s not proving a causal relationship,” Dr. Shepard clarifies. “We don’t know necessarily whether aspartame causes cancer.”

It’s a complicated question to research. Do people who eat a lot of aspartame get cancer because of aspartame? Or do high-aspartame consumers have something else in common — like a chronic health condition, vitamin deficiency or lifestyle choices — that leads to their increased cancer risk? After all, aspartame use is likely to be higher among people living with diabetes and obesity. Might those conditions be the root cause of a higher cancer risk?

As of now, we don’t know for sure, and the WHO’s designation of aspartame reflects that uncertainty.

The WHO ranks carcinogens into four groups based on how likely they are to cause cancer. Aspartame is listed as a “Group 2B carcinogen.” That’s the designation reserved for things believed to possibly cause cancer but that don’t have sufficient evidence to say they do for sure.

“Group 1 carcinogens are things we know cause cancer, like tobacco use and sun exposure,” Dr. Shepard explains. “Then, there’s Group 2A, which are things that probably cause cancer, like red meat. Group 2B is a step below that and includes things like car exhaust, lead and aspartame.”

Aspartame risks and side effects

In addition to its association with cancer, aspartame can come with some other unwanted effects.

Some scientists and physicians say sugar and artificial sweeteners like aspartame can be addictive in a way. They light up your nervous system, sending loads of feel-good hormones, like dopamine, throughout your body. It makes your body want more and more of the sweet stuff, which can lead to overconsumption.

What’s more is that some people may not react well to aspartame and other artificial sweeteners. The sugar alcohols used in making some artificial sweeteners can cause stomach discomfort, like bloating, cramps and diarrhea. And one common sugar alcohol, erythritol, has been linked to increased risk for heart attack and stroke.

Research on the long-term effects of aspartame has also linked it to a range of health conditions, like:

  • Obesity.
  • Diabetes.
  • Early menstruation.
  • Mood disorders.
  • Mental stress.
  • Depression.
  • Autism (when consumed during pregnancy).

But keep in mind that, like the connection between cancer and aspartame, more research is needed to determine the extent of the association between aspartame and those conditions.

Is it safe to have aspartame in your diet?

The WHO says that up to 40 milligrams (mg) of aspartame per kilogram (kg) of body weight is an acceptable daily intake. For context, one can of diet soda contains about 200 mg of aspartame. So, an adult who weighs 150 pounds (68 kg) could, in theory, drink about 13 diet sodas a day and stay within that limit, if they didn’t have any other aspartame in their diet.

But based on our current understanding of aspartame, Dr. Shepard advises caution and moderation. As in, even if the limits suggest 13 cans of diet soda is “acceptable” for you, it’s not recommended. Especially when you factor in the other potential effects of aspartame on your health.

“The risks of aspartame don’t mean that you should never have another diet soda or that you have to avoid aspartame at all costs,” Dr. Shepard clarifies. “But I see it as a reminder that moderation is important to lowering your risk.”

Alternatives to aspartame

If you’re looking to cut back (or cut out) sugar, aspartame and other artificial sweeteners, there are some better-for-you options to satisfy your sweet tooth.

Fresh and frozen fruit are the best choices for sweetening your food and drinks. That’s because, in addition to natural sugars, they’re packed with nutritional benefits, like fiber, vitamins and minerals. Try infusing water with sliced strawberries or slice of lime.

And some natural sugars, like raw honey, maple syrup and monk fruit may provide some health benefits. They’re still sugar, though, so you’ll want to go easy.

When considering your intake of aspartame, sugar, sugar substitutes and other less-than-ideal foods, Dr. Shepard says it’s a matter of being mindful about how you’re treating your body.

“It’s all about taking stock of whether, on balance, you’re doing good things for your body,” he continues. “Are you avoiding things that we know are very serious health risks? Are you managing your health conditions? Are you watching your weight? I don’t recommend doing anything drastic because most people aren’t likely to stick highly restrictive diets. Just be mindful that the things you eat and drink come with risk.”

Related Articles

Young female teen drinking canned beverage outside
December 26, 2023
The Young and the Restless: Why Kids Should Avoid Caffeine

No amount of caffeine is safe for kids under 12, and kids 12 to 17 should be cautious about how much they consume

Person eating a frosted pink donut.
November 9, 2023
Cheat Days: The Great Debate

These breaks may have some benefits — but they promote an unhealthy attitude toward food

Person making a selection from a food delivery app on their phone.
October 11, 2023
4 Ways To Kick a Food Delivery Habit

Be mindful, like gauging your hunger and reviewing nutritional information

Guarana seeds in the background on a wooden table with a spoonful of powdered gurarana suspended above.
July 16, 2023
No, Your Guarana-Laced Energy Drink Isn’t a Health Food

Guarana seeds may have benefits, but the potential is lost in processing

2 glasses of diet sodas with ice
May 18, 2023
Sad but True: Diet Sodas Are Bad for Your Health

Diet sodas are associated with weight gain, and may even cause insulin confusion

Lunch tray of processed foods.
March 22, 2023
What Ultra-Processed Foods Are (and Why They’re So Bad for You)

They’ve been altered to include fats, starches, sugars and hydrogenated oils

Fresh baked cookies using red dye with white frosting and red sprinkles
March 7, 2023
Is Red Dye 40 Safe?

The color additive found in many pre-packaged foods may affect those with ADHD or allergies

Person enjoying taco in a bowl at a street fair while talking on phone.
February 9, 2023
Making Healthier Fast Food Choices

Opt for lean, grilled meats, keep the portion size small and skip the soda

Trending Topics

glass of cherry juice with cherries on table
Sleepy Girl Mocktail: What’s in It and Does It Really Make You Sleep Better?

This social media sleep hack with tart cherry juice and magnesium could be worth a try

Exercise and diet over three months is hard to accomplish.
Everything You Need To Know About the 75 Hard Challenge

Following five critical rules daily for 75 days may not be sustainable

Person in foreground standing in front of many presents with person in background holding gift bags.
What Is Love Bombing?

This form of psychological and emotional abuse is often disguised as excessive flattery