An expert in brain science reveals he has a low carb diet with plenty of fish – and steak, bacon and wine at the weekend

The phrase “you are what you eat” might sound like hyperbole, but it has some truth to it, especially when it comes to the brain. Your diet can have a huge impact on your brain health.

As well as having an effect on the day-to-day function of your brain – those 3pm slumps after a carb-heavy lunch for example – your diet can impact the long-term health of the brain. “Lipid levels, obesity, diabetes and high blood pressure – all of which are related to diet – are proven risk factors for the development of dementia,” explains Dr Steve Allder, a neurologist at Re:Cognition Health in London.

This is something that research has confirmed too. One 2022 study, which followed 2,000 people over ten years, found those who consumed a lot of inflammatory foods – highly processed, and containing lots of sugar and saturated fats – had smaller brains and less gray matter, which are early markers for dementia. Obesity and type 2 diabetes have been shown to raise the risk of dementia, too, because they impact the brain’s ability to dispose of waste products.

Dr Allder, 55, says he started to pay more attention to his own diet and health when he hit his 40s. He has seen first hand how diseases like dementia can start to develop in midlife, long before you get symptoms: “The brain can be full of amyloid, the abnormal protein, at age 50, and that’s 20 years before you start to get symptoms.”

Here are some of the choices and changes he has made to his diet to maximise his brain health.

My breakfast is coffee and cream – and I never eat more than 2,000 calories

“In terms of diet, one thing that is definitely true is that calorie restriction helps the brain – that’s the most proven piece of evidence,” Dr Allder says.

“My baseline calorie intake is 1400 calories,” he explains, caveating that by saying: “I can’t, on the whole, stick to that, so I do enough exercise so that I can eat about 1800 to 2000 calories per day. I do about an hour and a half of exercise every day, at least, and I never eat more than 2000 calories.”

Generally, he avoids breakfast. “In the morning, I have a cup of coffee with some cream in it, and that pretty much allows me to get through to lunchtime,” he says.

I eat steak, but avoid chips

Dr Allder says he’s followed a low carbohydrate diet for a decade now. He tries to stick to eating carbs after exercise when his body is already in fat-burning mode. “If I do eat carbs, I feel more lethargic,” he says.

Dr Allder also says that restricting carbs has a positive impact on his day-to-day brain function: “Having moved to a lower carbohydrate diet, I feel sharper.”

For this reason he says he does not eat burgers, because of what the burger comes with, rather than the meat itself. “I would eat a good steak, or a good quarter pounder with cheese. But what I wouldn’t have now is the burger bun and chips.”

When Dr Allder does eat carbs, he tries to opt for high-fibre options, like brown rice. “I always go for brown rice – never white,” Dr Allder says. “It’s got more fibre in it so it causes less insulin spike.” One study on participants with an average age of 75 found that a high consumption of wholegrains was associated with a slower rate of cognitive decline.

I prioritise fibre and avoid UPFs

Dr Allder has started to take a daily fibre supplement called Myota to ensure he’s getting enough of the nutrient because of its positive effects on brain health. “There’s a guy at Massachusetts Institute of Technology and he was looking at how the microbiome influenced Alzheimer’s disease in rats,” Dr Allder says. “He found that the way to [improve] the microbiome in the rats was by having the right fibre because we all have very different microbiomes and different types of fibre react differently in all of us.”

“They developed some blends that, irrespective of which fibre you would ideally have, always has what you need,” Dr Allder continues, adding that he now takes this supplement daily. “Now, I don’t worry too much about whether I’m eating the right vegetables or the right meat. I know I’m definitely getting the right fibre.”

He avoids ultra-processed foods. “I don’t think there’s any doubt that the microbiome does not like [processed foods] and that, in turn, causes inflammation, which means the brain gets stressed out,” he says.

Sea bass, salmon and broccoli

“I am to eat oily fish three or four times a week,” Dr Allder says. “Sea bass and salmon are pretty low in calories, they’re wholefoods, they’re nutrient-rich, they’ve got healthy fats and fibre and importantly, I like them.

He cooks fish in oil, but says that: “Olive oil is the only oil I use” because it’s minimally processed.

One of the reasons fish is so good for brain health is that it contains Omega-3s, which a small study found can preserve brain health and enhance cognitive function in middle-aged people.

Green, leafy vegetables are rich in lots of brain-healthy vitamins, such as K, lutein, folate, and beta carotene. There’s one vegetable that Dr Allder opts for most: “Brocoli is high in fibre, which makes sure you’re not getting big insulin spikes, which can lead to tiredness and sluggishness. And scientifically, it dampens down inflammation, thanks to the antioxidants.”

Eggs and bacon at the weekends

Bacon is often considered one of the worst foods you can eat, as it’s ultra-processed and high in saturated fat. But Dr Allder allows himself to have it from time to time. “My wife looks at me disapprovingly every time I eat bacon,” he says. “But I only go for very high-quality meat and it’s a good combination of protein and fat with scrambled eggs and it works for me – it’s tasty and I don’t feel hungry.”

Dinner with friends and family

“The social experience of eating is really important,” Dr Allder says. “Studies show that it’s not just about the food but eating it together.

“So much of the time we’re ramming in food, eating on our own, rushing around. I definitely try to take time out to eat properly. I always make sure we try to eat together as a family each night.”

Two glasses of wine per week

“I do see people clinically who drink enough that it screws up their brain,” Dr Allder says, adding: “You’ve got to be going way over 40 units a week to do that. And the people I’ve seen who have it badly, they tend to drink in combination with recreational drugs, so it’s quite difficult to work out which one is the problem.”

Dr Allder limits his alcohol intake to two glasses of wine at the weekend. “Since turning 45, alcohol feels like poison – it affects my sleep massively,” he says. “I usually have one glass of wine on a Friday and Saturday night.” For long-term brain health, he says that sticking to the NHS guidelines of no more than 14 units a week is safe. “If you’re drinking more than that, you’re no doubt increasing your risk of dementia,” he says.

Almond, cashews and nut bars

Instead of crisps or processed foods, Dr Allder snacks on unsalted almonds and cashews. “They’re low in carbs and quite calorific so you don’t need to eat many and they fill you up,” he says. 

When short on time, he opts for nut bars such as KIND. “They’re about 150 calories, eight grams of carbs, 12 grams of fat and five grams of protein,” he says. “If I’ve got a busy day, I’ll have a couple of those and that will get me all the way through the day.” According to some research, nuts could help prevent memory loss.