Is there a link between IQ and healthy lifestyle?

Note: This is a section of a longer article. To go to the start, click here.

Not in general, but IQ was related to some specific behaviors. To  investigate this question, we asked our participants the following questions:

• How often do you eat at least one and a half cups of fruits?

• How often do you eat at least three cups of vegetables?

• How often do you eat fast food?

• How many days per week do you drink alcohol on average?

• How often do you smoke?

• How often do you use marijuana?

• How often do you use drugs other than marijuana or prescription drugs?

• Have you ever practiced meditation?

• How many days per week do you exercise on average?

Only for two of these outcomes IQ turned out to be a significant predictor: for drug use (other than marijuana and prescription drugs) where IQ predicted less drug use (r = -0.20, n = 660) and for smoking frequency (r = -0.13, n = 660) where IQ predicted less smoking. However, these correlations were small and all the other correlations were even smaller and non-significant. So we cannot broadly say that IQ generally predicts a healthy lifestyle. Below we show just  the two significant correlations.

What do the other studies say?

There were some studies conducted on large samples that found a more consistent relationship between IQ and healthy behaviors in general. For example, a study conducted on n = 5347 participants found that childhood IQ predicted later-life behaviors that are beneficial to health such as being more likely to be able to do moderate cardiovascular activity and strength training, being less likely to have had a sugary drink in the previous week, a lower likelihood of drinking alcohol heavily, being less likely to smoke, etc. (Wraw et al., 2018).Similar results were found in another larger study on n = 8282 participants by Batty et al. (2007). In this study children with higher mental ability scores reported significantly more frequent consumption of fruit, vegetables, wholemeal bread, poultry, fish, and foods fried in vegetable oil in adulthood. They were also more likely to have a lower intake of french fries, non wholemeal bread, and cakes and biscuits.

Takeaways

• IQ predicted only two of nine healthy behaviors that we measured

• Higher IQ people were less likely to use drugs and to smoke than people with lower IQ

• However, other studies have found broader positive links between IQ and healthy behavior that we did not find.

If you'd like to read the full report, of which this is a section, as one long PDF, you can download it here.

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