But surely the explanation behind the 'obesity epidemic' is far more complex than 'doctors started recommending low fat and high carb', as someone suggests early on. There are numerous other interlocking changes in how, when and what people eat in developed economies, where the problems of obesity are rife. For a start:
- snacking and the whole snackfood industry
- fizzy and flavoured drinks and fruit juices as the norm
- fast food and ready meals (often high in fat and carbs)
- increases in additives and flavour enhancers making cheap food taste good
- increasingly sedentary lives, due to motorised transport, white goods, electronics and all the other things we know about.
A high carb diet may be new in evolutionary terms, but it's common in less developed countries and in our recent past - both times/places with far less obesity. In early 20th c Britain people ate high carb and high fat - bread and dripping, potatoes, cakes for high tea - and they used more energy.
It seems clear that high levels of refined carbs aren't good for people, and I'm not an expert on the science, though I know that there are many seemingly reasoned rebuttals of the 'wheat bad, animal fat good' science too.
There are plenty of slim people who don't cut out any major food groups and eat what generations of people would consider a 'normal diet' - bread (staff of life, you know), vegetables, pulses, fruit in season, meat, fish, some sweet stuff.
You know, the basic mantra 'eat less and move more' (or rather, eat only as much as you need to for your energy requirements) is true.