You’re the world’s most powerful man, moving into the world’s most famous address. Your staff includes five full-time chefs, which is four more than most cafes. So what’s top of president Donald Trump’s shopping list? Lay’s potato chips and Doritos, that’s what.

Ah, crisps! Just the ticket for powering through a day of dubious decision-making and 3am tweets, no? Jo Travers, a dietitian and author of The Low-Fad Diet, is unconvinced. She is particularly worried about the impact of Trump’s diet (heavy on the fast food, easy on the veg) on his ability to think straight.

For starters, Trump barely touches anything containing omega-3s – the fats found in nuts, oily fish and flax seeds that our brain cells need to function. “His body will substitute with other types of fats, which are less fluid, making it harder for neuro transmitters to get through. This is linked to mood disorders,” she says – which might explain a thing or two ...

On the off chance Trump is up for a delayed new year health kick – we get it, he has been busy – Travers has a few pointers based on what he likes best.

On breakfast, which Trump skips if he can, or eats bacon and eggs if pushed, Travers thinks he should be “replenishing the nutrients his body can’t store overnight”. And cut down on the bacon. “It’s a processed pork product, which has been linked with cancer, so his risk of developing the disease will go up.” She would rather see a more even balance of protein and carbs. “His high-protein diet can put added pressure on his organs if he doesn’t drink enough water.”

When lunch is meatloaf, one of his favourites, Travers says it’s OK if he eats it in a sandwich (and apparently he does), again for the balance. She also advises brown bread. “Meatloaf is essentially just meat. There’s no roughage. And no fibre impacts on gut health. If you don’t feed your gut bacteria with fruit and vegetables, that can impact the immune system and lead to infections.”

For dinner, Trump’s favourites include a Big Mac or KFC bucket. Unsurprisingly, Travers warns that he risks overloading his body with trans fats, “which act like saturated fats, and they are linked to heart disease”. An overdone steak, Trump’s preferred choice, “isn’t necessarily bad, but burned food is linked to changes to our DNA, which can also cause cancers”.

She suggests his White House chefs might encourage Trump to embrace a few basic fractions when filling his plate. “It should be half-filled with fruit and veg, a quarter with carbohydrates and a quarter with proteins.” If that’s the key to thinking straight, it’s got to be worth a shot.