The Change Mariner

Junk food is fooling people into overeating

Times Online:

Fast food restaurants are feeding the obesity epidemic by tricking people into eating many more calories than they mean to, an important study has shown.

Typical menus at McDonald’s, KFC and Burger King contain 65 per cent more calories per bite than standard British meals, making it far too easy for customers to overindulge without realising it.

The high “energy density” of junk food — the amount of calories it contains in relation to its weight — throws the brain’s appetite control system into confusion, as this is based on the size of a portion rather than its energy content.

The critical role of energy density in obesity has been revealed by Andrew Prentice, Professor of International Nutrition at the London School of Hygiene and Tropical Medicine, and Susan Jebb, of the Medical Research Council Human Nutrition Centre in Cambridge.

In a study published in the journal Obesity Reviews, they calculated the average energy density of menus at McDonald’s, KFC and Burger King, using nutritional data from the fast food chains’ websites.

The average energy density of these restaurants’ meals was 1,100 kilojoules (263 calories) per 100 grams (4oz), 65 per cent more than the density of the average British diet and more than twice that of a recommended healthy diet. This means that a person eating a Big Mac and fries would consume almost twice as many calories as someone eating the same weight of pasta and salad.

Professor Prentice said that the human appetite encouraged people to eat a similar bulk of food, regardless of its calorific value. This left regular consumers of fast food prone to “accidental” obesity, in which they grew fat while eating portions they did not consider large.