Ketone bodies offer at least part of the explanation.
Ketone bodies are three natural compounds produced in the liver when the body metabolizes fat. Science shows the body can use ketones as replacement fuel when glucose -- the body’s preferred source of fuel -- isn't available.
This means that by drastically curtailing carbs and upping your fat intake, you can turn your body into “a fat-burning machine” as the keto marketers like to put it.
Given the popularity of the ketogenic diet, you probably have some idea what I’m talking about.
Ketones have already demonstrated anti-aging effects on other parts of the body, so scientists wondered whether they had the same effects on the brain. One of their findings came as a big surprise.
How Your Brain Ages
The brain only amounts to two percent of the body's volume, yet consumes over 20 percent of its energy. For this reason, the brain is especially vulnerable to changes in metabolism, the process by which the body converts food into energy.For example, researchers have found reduced glucose metabolism in people who suffer from Alzheimer's disease. What’s more, the greater the reduction in glucose metabolism, the more severe the dementia.
Of course, metabolic changes are a normal part of aging, but at what age these metabolic changes begin to affect the brain is really a mystery. A team of scientists from Stony Brook University, New York developed a study to find out.
Glucose Versus Ketones
They also investigated whether a diet rich in glucose, compared to a diet high in ketones, would affect the stability of brain networks and prevent memory loss.The researchers examined neuroimaging data sets from 926 people aged between 18 and 88. In addition, they scanned the brains of 42 adults under the age of 50 who spent one week on either a standard diet or a diet that's very low in carbohydrates – a ketogenic diet -- which produces more ketones through a process called ketosis.
Researchers scanned the brains of a third group before and after a drink of glucose on one day, and a drink of ketones on another. This was to make sure any changes seen in the diet groups were directly linked to the different energy supplies and not to some other factor.
Brain Aging Starts Early and Can be Stopped
The research team were surprised to discover that age-associated changes in the brain come about much earlier than they expected, around age 47, with the most rapid brain degeneration at age 60. But this finding had a silver lining: diet can alter these age-related changes."What we found with these experiments involves both bad and good news," said lead author Professor Liliane Mujica-Parodi.
"The bad news is that we see the first signs of brain aging much earlier than was previously thought. However, the good news is that we may be able to prevent or reverse these effects with diet, mitigating the impact of encroaching hypometabolism by exchanging glucose for ketones as fuel for neurons."
She went on to say that as people age, the brain loses its ability to metabolize glucose efficiently. This disrupts brain networks and neurons slowly starve. But their experiments showed that by switching to ketones as a source of fuel, brain energy is boosted and neuronal networks are saved.
Even in younger adults, those under age 50, supplying the body with ketones increased overall brain activity and stabilized brain networks. Researchers believe this is due to the fact that ketones provide more energy to cells than glucose. The effects are so strong that researchers found brain benefits from ketones as soon as 30 minutes after drinking the ketone drink.
“If we can increase the amount of energy available to the brain by using a different fuel, the hope is that we can restore the brain to more youthful functioning,” explained Prof. Mujica-Parodi.
Other studies had previously demonstrated similar results for the heart, but these experiments provide the first evidence for equivalent effects in the brain.
How to Generate Ketosis
You can induce ketosis with a diet very low in calories or carbohydrates, but few people can sustain this kind of diet over the long term.So how can we can reap the brain and heart health benefits of ketosis without going hungry or taking up a strict Paleo—meat rich— diet? The answer is that we probably can't.
However, we can induce mild ketosis which, the research shows, can still be extremely beneficial to the brain and heart.
One way is to consume ketone salts in capsules. This will increase blood levels of ketone bodies, but if the body isn't producing its own ketones, the effect won't last long after you stop taking the capsules. There is also no scientific evidence available that I can find on the long-term safety of using ketone salts.
Perhaps the safest and simplest solution is to:
- Keep carbohydrates relatively low in the diet as a general rule. Avoid all sugars and refined carbohydrates as well as minimize portions of starchy vegetables, fruit and whole grains.
- Avoid snacking, particularly between lunch and the evening meal.
- Severely restrict carbohydrates at dinner by eating meat, chicken or fish with a salad or vegetables. Better than animal products, eat healthy vegetable fats from coconut oil, avocado or nuts.
- Fast for 12 hours or more after the last meal of the day, which should be finished three hours before bedtime. Even better, go 16 hours without eating, for instance, from 6 PM to 10 AM the next morning.
I think this four-point strategy, aimed at producing mild ketosis, is a sound plan for a healthy person. If you’re using it to lose weight or treat a disease, however, it’s wise to have modest expectations. It’s not a magic bullet, as some supporters claim.
For example, taking large doses of coconut oil – a rich source of ketones -- yields amazing results in some patients suffering from dementia – but not all, and the benefits tend to fade after a time.
For cancer, the results of a ketogenic diet tend to depend on the type of cancer, and this course of treatment is best done under an experienced practitioner. As for weight loss, it seems it hasn’t been much more successful than most other diets.
And then there’s this: Most of us eat so many carbs that we could cut our intake in half and still be eating too much. Given this widespread problem, the low-carb diet fad is on the right track.
