The Donald Trump Diet, or Eat Yourself Furious!

From the outside, the whims and seasons of Donald Trump seem largely unpredictable. There he is, railing against the media he obsessively consumes, insisting that his inauguration numbers dwarfed the far-larger crowd at Barack Obama's, throwing tantrums about sketches on Saturday Night Live and periodically stopping to institute travel bans on people attempting to enter the US or insisting other countries will build him a wall. Who knows what he'll do next?

Then again, maybe it's more predictable than it appears. Could it be that science (science!) might have the power to offer some insights into the forces shaping the Trump mindset?

After all, we have a remarkable amount of data on what exactly goes into his body, and we also know that what we eat has enormous effects on how we feel and the way we function during the day.

So could it be that the food going into Donald Trump each day might be responsible for … um, everything that comes out of him, policy-and-other-wise?

With that premise in mind, we picked the exceptional brain of Michelle Challinor, lecturer in nutrition within the school of Environment and Life Sciences at the University of Newcastle.

"We know that nutrition does affect cognition, does affect mood, does affect behaviour," she explains. "And a lot of studies have been looking at potential links between obesity and mental health as well, especially later in life."

That's a good starting point since Donald Trump is the oldest American president ever. He's a 72-year-old man who, while 1.85 metres tall, could be politely described as "stout".

(And just parenthetically: those jokes about his tiny hands? The effect is due to the cut of his shirt cuffs and jacket sleeves which often pass his wrists, making him look as though he's wearing a size or two above what he should – a classic move for men secretly ashamed of their weight.)

He's not an active fellow either: sure, he enjoys a round of golf but is unlikely to have a quick one-on-one pickup basketball game, Obama-style, or even a John Howard power walk.

Indeed, the Washington Post claimed that his staff attempted to diminish the influence of media adviser Kellyanne Conway by deliberately giving her an office on the second floor, secure in the knowledge that Trump was unlikely to walk up a flight of stairs.

So. We have an elderly, overweight, fairly sedentary man in an exceptionally high-stress job. What's powering him, aside from Fox News and a sense of furious entitlement?

Breakfast: bacon and eggs

According to Trump himself, he doesn't care for breakfast and skips it when he can – but when pushed, he'll have "eggs done over-well and bacon cooked medium".

"Eggs are good," Challinor begins. "That's good protein, no major issue there. Bacon is processed meat high in saturated fat and salt and nitrates, so straightaway you've got things that aren't great. There's very little carbohydrate in there and we need that to fuel our brains, despite what paleo devotees will tell you. It's low in fibre, low in vitamins – there's some good B vitamins in the eggs, but not much else."

What would improve matters? "I'd recommend he'd need some grains: muesli or wholegrain toast, some yoghurt, some fruit, some tomato or some baby spinach or something, just a bit more variety: what he has is not a balanced breakfast and probably not going to fuel him for long."

Morning tea: nothing

Trump has proudly stated that he never drinks tea or coffee, although he chugs a lot of Diet Coke. He also replaced the Oval Office bowl of green apples – which was Obama's go-to when reading his morning briefings – for one filled with Frito-Lay potato chips.

"Well, obviously Diet Coke has caffeine in it," Challinor explains. "The calories are down because it has artificial sweeteners in it, but he'd be better off going for something a bit more natural – water would be a better option. Chips have carbohydrates, which are good, but essentially he's going from salt and fat to salt and fat. You're not getting a lot of vitamins out of a potato."

The long gap between eating is also an issue "because he's busy, he should be eating more regularly. He's more susceptible to sugar spikes because he's got a lot of carbs coming in. So he'll get an insulin spike, and then that'll drop – and that's when you get your mood swings of an afternoon, that lethargy."

Lunch: fast food

There's no shortage of photos of Trump chowing down on McDonald's, Taco Bell and buckets of KFC (eaten with silverware, because standards are standards) but most of them were taken on the campaign trail where you'd reasonably expect him to be forced to grab food on the fly.

It turns out, however, that his fondness for Big Macs and taco bowls isn't entirely about convenience. He's discussed at length his theory that takeout places have the planet's most assiduous standards of hygiene.

As he told CNN, "One bad hamburger, you can destroy McDonald's, they're out of business. I like cleanliness, and I think you're better off going there than maybe someplace that you have no idea where the food's coming from. It's a certain standard."

"Again, it's high saturated fats, high salt levels – and look, we need sodium in our diet for nerves and muscles and so on, but that's way too high in sodium," says Challinor.

"You're looking at hypertension, blood pressure going up, much higher risk of cardiovascular diseases and strokes. For lunch he should be looking at salads, vegetables, lean meats, good oils – look more to the Mediterranean diet, more fish and legumes and olive oil."

Dinner: low-quality meats

This is Trump's big meal of the day, and he especially enjoys a very, very, very well-done steak (as his butler described it to The New York Times, "It would rock on the plate, it was so well-done") and a caesar salad.

"Caesar salad?" Challinor says with incredulity. "OK, you've got what, a bit of iceberg lettuce? And that's drowned in a high fat, high salt, high sugar dressing with bacon and croutons and eggs. Bit of fibre, but not much else there, is there? The steak's at least a good source of iron and protein, though."

Trump has also praised the culinary skills of his wife Melania in interviews, although the only examples he cited were spaghetti with meat sauce and meatloaf – presumably as two separate meals rather than combined in the one bucket.

"Well, if you're looking at meatballs and meatloaf it's mince, so you're probably looking at poorer quality meat with higher saturated fats. And again, where are the vegetables? Pasta, we can probably make the assumption it's white pasta so it's going to be high glycaemic index. Spaghetti sauces are typically high in sugar, lot of salt, not much fibre. The poor man must be horribly constipated!"

In other words, those early morning tweets are very probably fuelled by indigestion, insomnia and IBS as much as his contempt at Arnold Schwarzenegger taking over on The Apprentice. It's also not seemingly being offset by other healthier choices.

"If Trump's not getting much physical activity I'm not sure why he's not more obese than he is, to be honest. And you'd expect him to be stressed too, producing a lot of [the hormone] cortisol which that has all sorts of effects on mental health, as well as leading to insulin resistance and pre-diabetes. He doesn't strike me as a man that's very cool, calm and collected."

The longer-term results are equally worrying.

"With that level of saturated fats there's an elevated risk of atherosclerosis, where plaques form in your blood vessels. That's going to predispose you to heart attacks and strokes, but anything that affects your blood flow also affects your brain so cognition's going to be down. And he's probably having mood crashes because of his insulin levels – that's what being 'hangry' is about – so his behaviour has got to be influenced by his nutrition."

Could there be something other than his diet keeping things on more even a keel than it would appear?

"Maybe he's taking amazing amounts of multivitamins and supplements each day, but we know that supplementation is not as effective as eating it in the whole food state. They don't work individually: you can't just take Vitamin C or B2 tablets and hope they're going to do the same job as eating an orange."

So overall, not a great diet for an older gentleman in a high-pressure job?

'It's just lacking variety," she summarises. "He needs fruits and vegetables and legumes to get those essential nutrients. He's not getting vitamins and minerals in abundance there, not fibre, not a good steady flow of carbohydrates – and your body can convert stuff into carbs, but it's hard work."

And finally, the most important question: if Malcolm Turnbull needs to make a phone call to Donald but wants to avoid repeating their humiliating clash from January, when should he time it to catch Trump at his least volatile?

"I'd be calling right after breakfast, I think," Challinor suggests. "He's had a bit of a sleep, he's had his bacon and eggs so his belly's full, but he wouldn't have started to digest too much so his blood sugar should still be reasonable."

World leaders, consider yourselves advised. Future global diplomacy may depend on it.