[RobertG (OP)]

There's been a lot said lately about poor metabolic health (particularly insulin resistance) brought about by poor diet, and it being responsible for worse outcomes in Covid19, as well as diabetes, CVD etc.
Are we the only animal on earth, who seem obsessed with eating and drinking things that are bad for us?
Is there a kind of 'switch' in human genes that could be activated to stop us being so stupid?
Naive question I know but trust me I'm not a scientist!

[alancalverd]

There may be a few oddballs who deliberately eat stuff known to be poisonous or infectious, but obesity is due to overindulgence in stuff that we actually need, and COVID susceptibility seems to be enhanced by a lack of vitamin D, i.e. a dietary insufficiency, not surplus.

Zoonotic infection is a rare occurrence, and it can be argued that the success of Caucasian peoples in particular derives from the development of an agriculture that minimises the likelihood of pathogen transmission from our prey species - it's very difficult to survive in northern Europe on native vegetation. The problem with COVID is in the stupidity of those in authority and the general public for failing to publicise, contain and eradicate it - very few people outside Wuhan have contracted it from bats, but millions from other humans.         

[Bored chemist]

Are we the only animal on earth, who seem obsessed with eating and drinking things that are bad for us?

No.
Plenty of our pets are also overweight.
We (well, the wealthy ones among us) are the only animal that can reliably find far more food than we need.

Is there a kind of 'switch' in human genes that could be activated to stop us being so stupid?

Sort of.... it's called education.
Some of our leaders don't seem to be in favour of it for most children.

[RobertG (OP)]

What I primarily meant about eating things that are bad for us, was overeating carbs, particularly raw sugars, processed fats, and alcohol.

[Bored chemist]

What I primarily meant about eating things that are bad for us, was overeating carbs, particularly raw sugars, processed fats, and alcohol.

Most animals are more or less hungry more or less all the time.
And if you are hungry, those are really good things (carbs, fats and sugars) to eat.
They will supply the energy you need to stay alive.