Diet Coke Probably Isn’t Giving You Cancer

Why the aspartame in artificially sweetened foods probably isn’t worth worrying about

Gideon M-K; Health Nerd
5 min readJun 30


Pictured: Probably not carcinogenic. Photo by Kenny Eliason on Unsplash

Aspartame is an artificial sweetener that is used in a lot of products, including Diet Coke and Coke Zero. Like most artificial sweeteners, we have a wonderful love/hate relationship with it. It’s sweet but doesn’t have any calories, so it’s great for people who want to lose a bit of weight. Also, a bunch of people are convinced that anything artificial is basically poison, and that diet soft drinks are probably killing us all.

This has hit the headlines recently, because apparently the International Agency for Research on Cancer (IARC), a World Health Organization body, is preparing to declare aspartame a class 2B carcinogen. This has caused a huge uproar, because aspartame is one of the most commonly-used artificial sweeteners in the world, and also because cancer is very scary.

Fortunately for people like me, who really like our diet drinks, the evidence really isn’t that compelling. Aspartame probably isn’t giving you cancer.

IARC Categories

The first point to consider in this discussion about aspartame is the way that the IARC classifies things that could potentially cause cancer in human beings. They have four categories:

1 — Causes cancer

2a — Probably causes cancer

2b — Possibly causes cancer

3 — Unclassifiable as a cancer risk

There are a few interesting points to make here off the bat. Firstly, the IARC doesn’t ever consider the magnitude of risk. There are class 1 carcinogens that cause cancer in every person exposed to them, and other class 1s that almost never cause cancer even in massive, lifelong doses. For example, both processed meat and plutonium are considered class 1 carcinogens, even though the risk from bacon is decidedly lower than that posed by nuclear explosions.

Pictured: Less risky than an atom bomb. Photo by Wright Brand Bacon on Unsplash