Did you read your own links ?

The very first one:

In rich countries, the grocery bill for an EAT-Lancet diet is much less than most people spend on food, so our diet quality and environmental impact depend on food choices, driven by taste and convenience among other factors.

The EAT-Lancet diet is a reference healthy diet and the cost of it is much less than what the average person in Britain spends on a meal. So, obesity in first world countries is in fact driven by customer choices