In the US we have crazy corn subsidies. So fillers and sweeteners are crazy cheap. If you are processed food maker up can easily bump up calories and portions by adding corn or wheat gluten to the product and pump a ton of corn syrup into it make it taste better. So you can price cut healthier options by reducing the actually quality foods(meat, vegetables) and replace it with corn and sugar. Also prepaid healthy food is aimed at people who are more willing to spend money on convenience and quality, who are less price concerned. This is mainly for the processed foods though healthy fresh foods are very price competitive.  my theory:  Most fatties eat a lot of processed foods so they eat a ton of fillers. If you have a basic understand of cooking, i.e. how to use a rice cooker and cut vegetables you save a lot of money and get high quality foods.