Dietitian Glenn Cardwell delivers the verdict on one of the most persistent food myths: that eating chocolate gives you pimples.
When you were a teenager, did your mum or anyone else tell you that eating chocolate would give you pimples? While they may have thought it was helpful advice, back then there probably wasn’t much evidence to back it up.
So is it true? Depends on who (and when!) you ask. Most of the diet and acne research conducted in the 20th century wasn’t high quality, and it led dermatologists to the view that food probably didn’t make much difference to pimple production.
However, that view changed in 2002. A new theory stated that, since non-Westernised societies have almost no acne, it is our Western diet of high Glycaemic Index (GI) foods which stimulates the formation of pimples. The theory is that because high-GI carbohydrate foods are digested quickly, they raise blood glucose levels too high and trigger high levels of insulin in the blood. This elevates Insulin-like Growth Factor 1 (IGF-1) which, in turn, stimulates sebum production. Sebum is an oily substance that naturally rises to the surface of the skin on the face, back and chest. Should this flow become blocked, the sebum accumulates. Bacteria then feed on the sebum and bacterial growth can lead to pimples, or even acne, forming.
The theory that high-GI foods cause pimples has been given even more credibility by recent Australian research on the link between diet, hormones and acne. The study was conducted on a group of male teenagers and it confirmed that a high-GI diet influences hormones to promote acne development. Scientists now generally agree that the GI theory of acne has the best support.
So if high-GI foods cause pimples, is it fair to blame chocolate? As chocolate has a low- to moderate GI (and a moderate insulin response), it doesn’t seem likely that chocolate is the sole cause of an emerging pimple. If there is a link, it is more likely because chocolate may have been eaten during a time when you were following a poorer quality diet, which included high-GI foods.
The best dietary defence against pimples and poor skin is healthy eating – a high-quality diet (which usually includes lower GI foods) typically results in fewer pimples. Choosing highly processed foods tends to lead to higher blood glucose levels, higher insulin, changes in hormonal levels and a greater chance of waking up in the morning with a huge pimple staring back at you in the mirror.
The bottom line
Chocolate alone won’t cause pimples – a poor quality diet, with lots of high-GI foods, over a period of time may be the culprit.