How meals affect the performance of your brain and body
Does eating just a rice ball have the same effect as eating nothing at all?
We investigated the actual effects on the body -body temperature, feelings of fatigue, and ability to perform mental tasks- of eating versus not eating breakfast, and of what one eats.
Participants in the study were divided into four groups: a group that ate a western-style breakfast, a group that ate nutritionally balanced food bars, a group that ate rice balls, and a group that ate nothing.
The participants were 20 healthy adult males who eat breakfast habitually. The study was conducted four times with seven days between each trial.
Study outline
| Objective | To investigate the effects of skipping breakfast and the type of breakfast on body temperature, subjective symptoms such as feelings of fatigue, and ability to perform mental tasks. |
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| Subjects | 20 healthy adult males with no habit of skipping breakfast Age: 32.7±3.5, BMI: 22.2±2.5 (mean±SD) |
| Study Design | Unblinded crossover test (random allocation)*
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| Test articles |
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Result
First we investigated how body temperature changes depending on the type of meal. The tests started with all the groups eating their test breakfasts at 8am.
Body temperature was nearly the same in all groups just before eating and rose in all groups as time went on.The group that ate a western-style breakfast felt less tired than the group that ate no breakfast. The group that ate nutritionally balanced food bars also felt less tired, to the same degree as the group that ate the western-style breakfast.
- The group that ate nutritionally balanced food bars also felt less tired, to the same degree as the group that ate the western-style breakfast.
We used the visual analog scale (VAS)*1 to investigate how the feeling of fatigue changes with time. In the group that did not eat breakfast, the feeling of fatigue increased with time.
The feeling of tiredness in the group that ate rice balls dropped at around 8:30am, 30 minutes after eating, and then steadily increased up until 12pm.
In the group that ate a western-style breakfast, the feeling of fatigue also increased gradually from 8:30am; however, the rate was lower than that in the group that ate rice balls at almost all times.
The group that ate nutritionally balanced food bars experienced similar levels of fatigue as the group that ate a western-style breakfast.
- *1Visual analog scale (VAS)
VAS is a method of quantifying subjective feelings by having subjects mark a point along a horizontal line with contrasting items at each end. The distance from their mark to either end shows the degree to which they associate with the two statements specified.
- The group that ate a western-style breakfast felt less tired than the group that ate no breakfast.
- The group that ate nutritionally balanced food bars also felt less tired, to the same degree as the group that ate the western-style food.
We also used VAS*1 to investigate the level of concentration during mental tasks.
The level of concentration in the group that ate no breakfast declined from the start of the tests at 8am, until 10:30am, and then increased slightly thereafter. This group had the lowest level of concentration at all points in time.
The group that ate a western-style breakfast could concentrate extremely well during the 30 minutes after eating breakfast, after which concentration levels declined gradually. However, concentration remained high throughout the test.
As with the group that ate the western-style breakfast, the group that ate nutritionally balanced food bars also showed a high level of concentration at all points.
- *1Visual analog scale (VAS)
VAS is a method of quantifying subjective feelings by having subjects mark a point along a horizontal line with contrasting items at each end. The distance from their mark to either end shows the degree to which they associate with the two statements specified.
- The group that ate a western-style breakfast maintained a higher level of concentration than the group that ate no breakfast.
- As with the group that ate the western-style breakfast, the group that ate nutritionally balanced food bars maintained a high level of concentration.
We investigated how the ability to carry out mental arithmetic changes over time*2.
- *2Work effectiveness test: Using an Uchida-Kraepelin test form, subjects performed one column addition three times for one minute each with one minute between each round
No major difference was seen between the group which ate no breakfast and that which ate rice balls during the test period.
However, the group that ate a western-style breakfast and the group that ate nutritionally balanced food bars showed an increase in mental arithmetic efficiency after eating. The group that ate nutritionally balanced food bars in particular had an increase in mental arithmetic output in the second half of the test.
- The group that ate a western-style breakfast and the group that ate nutritionally balanced food bars showed an increase in mental arithmetic skills after eating. Their mental arithmetic output was significantly higher than the group who ate no breakfast, especially in the second half of the test.
When compared to the group that ate a western-style breakfast, the following differences were observed in the group that skipped breakfast:
- Body temperature rose more slowly.
- Felt more tired.
- Had a lower level of concentration.
- Were slower at mental arithmetic.
The group that ate nutritionally balanced food bars had the same results as the group that ate the western-style breakfast, demonstrating the importance of having a well-balanced breakfast.