Does fasting or eating less help your memory and concentration?
There are cautious indications that eating considerably less may improve your memory, but the evidence is still thin. Healthy people looking to improve their concentration cannot rely on fasting as a proven strategy.
Eating 30% less for three months improved verbal memory in healthy older adults by an average of 20%. This finding came from a small intervention study with fifty participants around the age of sixty who were slightly to moderately overweight. The improvement coincided with lower insulin levels and fewer inflammatory markers in the blood. Participants who continued eating normally but tried to consume more unsaturated fats did not see a similar improvement. One small study is not proof, however; the finding is nonetheless a serious signal worth noting.
Intermittent fasting, the alternation of eating and fasting periods, has no clear short-term effect on memory or concentration in healthy people. That is the conclusion of a Dutch review article. There are indications from animal research that fasting protects the brain by temporarily running it on an alternative fuel (ketones). This switch activates processes that appear to strengthen brain plasticity. Whether that also leads to measurable cognitive gains in healthy people has not yet been demonstrated.
In people with epilepsy, multiple sclerosis or Alzheimer's disease, there are cautious indications that fasting may be beneficial. In animals, caloric restriction reduces the accumulation of the protein that is characteristic of Alzheimer's disease, and appears to keep cerebral blood vessels healthier. Long-term clinical studies in humans are largely absent, however. Recommendations for sick or vulnerable people are therefore still premature.
How you fast also matters. Fasting during the day, as during Ramadan, can actually have a negative effect on decision-making and mental performance. Other forms of fasting do not appear to have that effect, or even have a slightly positive mechanistic effect through a protein that stimulates brain growth. It is therefore not the case that every form of fasting has the same effect on the brain.
Multiple review articles conclude that eating less slows brain ageing in animals and may also reduce age-related memory problems in humans. Those conclusions remain controversial: the exact mechanism in humans is still unclear, and the safety and feasibility of long-term caloric restriction have not been studied thoroughly enough to base general recommendations on.
Seven reviews and one small intervention study (n=50). No meta-analyses. The only direct intervention study in humans is small and therefore of limited generalisability. Most mechanistic insights come from animal research.
Does creatine also help with memory and concentration?
Creatine can improve your memory, but mainly if you are older, vegetarian, or your brain is under pressure. If you are a young, healthy meat-eater who sleeps well, the effect is small to negligible.
What does your estrogen level do to your memory and concentration?
Oestrogen has a measurable influence on memory and concentration, and the decline during perimenopause is accompanied by temporary cognitive complaints in many women. Whether hormone therapy reverses this depends on timing and individual circumstances; discuss this with your doctor if it is affecting you.
Does green tea help improve your memory or concentration?
Green tea offers a modest but real benefit for concentration and working memory, primarily thanks to the combination of caffeine and L-theanine. Do not expect a major leap in cognitive performance, but a daily cup of green tea is a well-supported choice as a small boost.
Can thyroid problems worsen your memory and concentration?
A clearly underactive or overactive thyroid can noticeably affect your memory, concentration and mood. With mild thyroid problems that link is far less clear, so have your complaints investigated by your doctor before drawing conclusions.
Does a fasting-mimicking diet work better than simply eating less?
A fasting-mimicking diet has promising effects on several health markers, but whether it works better than simply eating less has not yet been demonstrated. If you want to try it, be aware that independent long-term data are still lacking and that the costs of commercial packages are a real consideration.
Does fasting (intermittent fasting) help improve your insulin levels and other hormones?
Fasting probably improves your insulin levels, but most studies are small and short-term. Eating early in the day appears to be most effective; be aware of possible muscle loss if you are older or physically vulnerable.