Is sugar really bad for you?

Given the current situation, many of us are more interested than ever in how food can (and can’t) support our health. To help you sort out fact from fiction, BBC Future is bringing back some of our most popular nutrition stories.

Our colleagues at BBC Good Food are also focusing on practical solutions for ingredient swaps, nutritious storecupboard recipes and all aspects of cooking and eating during lockdown.

It’s hard to imagine now, but there was a time when humans only had access to sugar for a few months a year when fruit was in season. Some 80,000 years ago, hunter-gatherers ate fruit sporadically and infrequently, since they were competing with birds.

Now, our sugar hits come all year round, often with less nutritional value and far more easily – by simply opening a soft drink or cereal box. It doesn’t take an expert to see that our modern sugar intake is less healthy than it was in our foraging days. Today, sugar has become public health enemy number one: governments are taxing it, schools and hospitals are removing it from vending machines and experts are advising that we remove it completely from our diets. It has even been blamed for possibly increasing the risk of contracting infections because it allegedly suppresses the immune system, although in reality the impact it has on our ability to fight off diseases is a great deal more complicated than that.

And so far, scientists have had a difficult time proving how it affects our health, independent of a diet too high in calories. A review of research conducted over the last five years summarised that a diet of more than 150g of fructose per day reduces insulin sensitivity – and therefore increases the risk of developing health problems like high blood pressure and cholesterol levels. But the researchers also concluded that this occurs most often when high sugar intake is combined with excess calories, and that the effects on health are “more likely” due to sugar intake increasing the chance of excess calories, not the impact of sugar alone.

Meanwhile, there is also a growing argument that demonising a single food is dangerous – and causes confusion that risks us cutting out vital foods.

Sugar, otherwise known as “added sugar”, includes table sugar, sweeteners, honey and fruit juices, and is extracted, refined and added to food and drink to improve taste.