How unhealthy is fast food?

Professor David Cameron-Smith weighs up the nutritional value of fast food to assess.

Written by David Cameron-Smith

Fast foods dominate our lives. One in four of all meals are purchased and eaten outside of the home, and most of these are convenience- and taste-driven fast foods. Fast food also extends to what is eaten inside the comfortable walls of home. An endless array of pre-prepared food options are available on supermarket shelves, all designed to speed up the process of preparing and eating on the run or at home.

We all know too much fast food is bad for us. But what exactly makes it unhealthy? Here’s a closer look at some things to know…

High energy density

Is it fat or carbohydrates that make us gain unwanted kilograms? The correct answer is both. Most fast food contains an extensive array of fats and carbohydrates, often as sugar, that ensures fast foods contain more energy (kilojoules) per bite than most foods.

High in saturated and trans fats

Saturated fats are part of the texture and aroma of many fast foods. Many healthier types of fats just don’t work as well and when used there is a risk that the high temperatures used in the cooking may generate trans fats. Trans fats are the chemical by product of heat and oxygen on some healthier mono- and poly-unsaturated fats. Both saturated and trans fats increase the risks of heart disease by modifying the way fats are transported in the body, increasing cholesterol and other compounds in the blood.

Low nutritional value

Fast foods, while being full of fats and sugar, are low in many of the vital nutrients and minerals needed for optimal health. Dietary fibre is one casualty, with most fast foods providing only a gram or two of the 25 grams recommended each day.

Most vitamins and minerals, particularly those found in vegetables are also lacking in fast foods. The few limp pieces of lettuce, onion and tomato that might be found in some fast foods provide little of the vast array of antioxidants found in whole plant foods. The one mineral added in excess is sodium (as sodium chloride otherwise known as salt).

Sugary drinks

Eating fast food, especially if eaten fast, is thirsty work. Most carbonated beverages are high in sugar and some contain a hidden caffeine punch. Scientific debate rages on whether sugar-rich drinks add to our expanding waistlines, but there is no doubt that the added kilojoules from the hidden teaspoons of sugar dissolved in these drinks adds more energy that the body must somehow use.

Healthier fast food choices

Not all fast food is bad, and there is an increasing shift to see healthier fast food options pop up when the demand is high. Around offices and areas where consumers have more money to spend, healthy food choices are likely to be available. Sure, it costs more, because food that is made fresh and contains perishable fresh vegetables will naturally be more expensive, but price isn’t everything. If you need to eat fast, your body will thank you for choosing healthier options whenever you can.

Written by David Cameron-Smith

Professor David Cameron-Smith is a health expert and the current Chair in Nutrition at the Liggins Institute, University of Auckland.

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