Is sugar the real culprit?

Until recently, healthy eating advice in the UK has been focussed on reducing dietary fats and replacing them with complex carbohydrates. This is based on the link between a high-fat diet and heart disease. But now the low-fat mantra is being questioned. Should we be more concerned about high levels of sugar intake?

The truth about sugar

Sugar is now added to many foods – particularly breakfast cereals, processed foods, drinks and confectionary. Sugar is also added to low-fat products to replace the flavour lost through the removal of fat. So why is sugar a problem? 

  • Sugar has an addictive quality that makes it hard for us to resist. Foods with added sugar sell better, especially to children.
  • Foods with excess sugar are low in nutrients and higher in calories – inevitably leading to weight gain. 
  • Eating too much sugar can cause tooth decay. 
  • Sugar is a refined product that digests quickly and raises blood sugar fast (high GI), stimulating a large release of insulin. Insulin is your body’s ‘storage’ hormone, taking nutrients from the blood into the cells, whilst at the same time preventing your body from burning any stored fat for energy. If sugar is used excessively, the body will become insulin resistant, obese, and eventually type-2 diabetic.

A note on fructose

A type of sugar called fructose, or ‘fruit sugar’ has come under special scrutiny because of how it is metabolised:

  • Fructose is metabolised primarily by the liver, and large amounts arriving at once from a refined, sweetened product can make it hard for the liver to cope. Non-alcoholic fatty liver disease (NAFLD) is now quite common in the UK and links are being made between the condition and high intakes of fructose.
  • High-fructose corn syrup (HFCS) in particular has been identified as a problem in the modern diet. HFCS is cheap to produce and a very effective sweetener, making it widely used by soft drinks manufacturers in their products. 
  • Fruit juice is also very high in fructose and, despite its healthy image, is increasingly recognised as just another source of refined sugar.

Fruit: sweet enough? 

Is fruit itself bad for us? Although fruit does contain fructose, it is naturally combined with lots of fibre when eaten as the whole fruit as nature intended, and the fibre slows the release of fructose so that your liver can metabolise it comfortably. Whole fruit is still good as part of your 5-a-day; it is the refined juice that causes the problem.

Cutting down

After decades of worrying about high fat foods, we still find ourselves in the midst of an obesity crisis, and there seems to be a consensus amongst dieticians that there is indeed a problem with eating too much sugar. But being aware of how much sugar we are eating doesn’t mean we should let fat off the hook! 

If you want to lose weight and improve your overall nutritional health, you should be aware of the sugar added to your foods as well as the fat. The best way to do this is to avoid the main sugary offenders such as fruit juice, refined breakfast cereals, soft drinks and processed foods in general. 


About the author: 
Tim Shaw is the author of the Central YMCA guides ‘The need to know guide to Nutrition and Healthy Eating’ and ‘The need to know guide to Nutrition for Exercise’. Tim is an experienced instructor in the health and fitness industry, specialising in teaching the principles of exercise, nutrition and healthy eating to gym instructors and personal trainers. He has worked for London Central YMCA as a tutor in health and fitness for over 20 years.

ymca | 30 January 2015