The report says there has been an increase in the calorie density of food eaten by 2.6%, less for poorer people. Fat density has increased by 2.4%, less for the poorer people. Sugar density has increased by 2.1%. So we have increases of between 2% and 3%, which doesn't seem to be a big change. What's more salt density has decreased by 7.5% and fibre density has increased by 4.1%, which is quite a good thing. So the food we eat has become slightly fattier and slightly more sugary, but at the same time less salty and with a higher fibre content.
At the same time people have been spending less on food and eating fewer calories. The amount of fat, sugar and salt eaten have been decreasing. One way you can interpret the statistics is to say that people are eating slightly less food overall, eating the same proportion of processed food, but eating cheaper processed food. Cheap processed food does seem to have more fat and sugar than the more expensive processed food.
What people don't seem to be doing is turning to the cheaper less processed foods such as rice and pasta. The assumption that the Institute of Fiscal Studies are making is that calorie dense foods are cheaper. It might well be that a macaroni cheese from Iceland is more calorific and cheaper than the equivalent from Marks and Spencer. However, less processed foods such as rice and pasta are much cheaper than the cheapest processed foods. So to say that the poor have had no option but to turn to more calorie dense foods is wrong.
