The Psychology of Lifestyle (II)

For general comments about the book, see my first post. In this post I’ll add some more observations of interest from the book.

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“[M]any [children] show fear and avoidance of novel foods. The tendency to reject novel foods has been termed neophobia. Research has begun to reveal how early experience and learning can reduce the neophobic response to new foods, thereby enhancing dietary variety. For example, Birch and Marlin (1982) found that when 2 year olds were given varying numbers of opportunities to taste new fruits or cheeses, their preferences increased with frequency of exposure. Researchers found that between five and ten exposures to a new food were necessary before preference for that food increased. In another study, Gerrish and Mennella (2001) investigated the acceptance of a novel taste (pureed carrot) by infants who had previously experienced a range of tastes that included many vegetables but not carrot. Exposure to fruit, carrots alone or a variety of vegetables resulted in an increased acceptance of pureed carrot. Furthermore, those who had been exposed to a variety of vegetables were also more likely to eat other novel foods. Researchers concluded that familiarity with a variety of flavours increased the acceptance of novel foods. The implication was that parents should expose their children to a wide variety of tastes to encourage the acceptance of novel foods. […] exposure is a major factor in encouraging consumption. […] during childhood, the neophobic response to new foods decreases with age […]. Although repeated opportunities to taste and eat new food has been found to reduce neophobia and enhance acceptance, merely smelling or looking at the food has no such effect (Birch et al. 1987). This finding is consistent with the learned safety hypothesis which suggests that neophobia is only reduced as we learn that the food is safe to eat and does not cause illness […]. Further evidence suggests that watching others consume the food may provide a form of ‘exposure by proxy’ or modelling which could also reduce rejection […] observing a parent eating energy dense food could potentially encourage a child to establish similar food preferences. The effectiveness of the role model has been found to differ depending on the relationship between the child and the model. […] Birch (1980) and Duncker (1938, cited in Birch 1999) report that older children are more effective role models than younger children; Harper and Sanders (1975) report that mothers are more effective than strangers; and for older preschool children, adult heroes are more effective than ordinary adults (Birch 1999).”

“Promise of a reward is a time-honoured parental tactic for promoting consumption of healthy food. Nevertheless, it has been argued that treating food consumption in this way may actually decrease liking for that food. Lepper and Greene’s (1978) overjustification theory argues that offering a reward for an action devalues it for the child. In support of this a number of studies have reported decreased liking for foods when children are rewarded for eating them […] Horne et al. (2004) argue that in order for rewards to be effective, it is important that they are highly desirable and that they indicate to the child that they are for behaviour which is enjoyable and high status. Other studies have investigated the impact of using food as a reward. For example, Birch et al. (1980) presented children with foods either as a reward, a snack or in a non-social situation and found that acceptance increased if the food was presented as a reward. It is easy to generalise this finding to real life situations. High fat and sweet items are used repeatedly in positive contexts, for example on special occasions. The consumption of already pleasurable items in this way is reinforced. If children are given foods as rewards for approved behaviour, preference for those foods is enhanced (Benton 2004).”

“Cognitive models of eating behaviour explore the extent to which cognitions predict and explain behaviour. Most research from a cognitive perspective has drawn on social cognition models and several models have been developed […] All […] share the assumption that attitudes and beliefs are major determinants of eating behaviour, however they vary in terms of the cognitions they include and whether they use behavioural intentions or actual behaviour as their outcome measure […] Some research using the TRA and TPB has focused on predicting behavioural intentions. Research suggests however, that behavioural intentions are not that successful in predicting actual behaviour.”

“Traditionally habit has been measured by the number of times behaviour has been performed in the past […] Nevertheless behavioural recurrence does not constitute direct evidence for habitual processes. Verplanken and Orbell (2003) argue that habit is a psychological construct rather than behavioural recurrence and involves lack of awareness, difficulty to control, mental efficiency and repetition. Although repetition is a necessary requirement for a habit to develop, subsequent research has supported the hypothesis that frequency of past behaviour and habit are separate constructs [I also pointed this out elsewhere recently, but I think it’s an important insight. Revisiting my coverage of Buskirk et al.’s text after posting that comment I incidentally realized that Eysenck and Keane‘s coverage may well in some respects be more relevant/useful than the former.] […] It may be […] useful to conceptualise habits as established patterns of behaviour that may once have been initiated by rational choice but which are now under the control of specific situational cues that trigger the behaviour without cognitive effort. […] Reasoned action as represented in social cognition models and habit can be considered as two extremes of a conscious decision-making continuum. In between may lie a number of heuristic decision-making strategies that involve varying degrees of cognition.”

“Foltin et al. (1988) gave volunteers two cigarettes containing active marijuana or a placebo and found that active marijuana increased total caloric intake by 40 per cent. […] studies exploring the relationship between alcohol and food intake have been contradictory. In a mini-review Gee (2006) found that among eight studies reviewed, only one showed a significant difference in appetite ratings between the alcohol and no alcohol pre-load. […] Gee (2006) concluded that the effect of alcohol on appetite appears to be unsubstantiated; however alcohol’s effect on energy intake does appear significant. As well as recreational drugs, anti-psychotics and antidepressants have also been shown to influence hunger and satiety.” [Of course there are a large number of variables involved, but they don’t actually go into much detail in their coverage. To add to the list, sleep can also be quite important].

“According to Bourn (2001) approximately two-thirds of the UK’s population visit their GP at least annually, so primary care provides an unparalleled opportunity for health promotion and preventive interventions.” (This number is old, but a number like this one seems relevant to a wide variety of topics so even if it’s dated I decided to include it here anyway in order to increase the likelihood that I’ll remember the context of the estimate later).

“Despite considerable efforts over a number of years, there is limited evidence to suggest that educational approaches to dietary change (that is providing basic information about what constitutes a ‘healthy’ diet) alter children’s eating habits […] Hundreds of interventions to combat the obesity epidemic are currently being introduced worldwide, but there are significant gaps in the evidence base for such interventions and few been evaluated in a way that enables any definitive conclusions to be drawn about their effectiveness. Those that have shown an impact are limited to easily controlled settings and it remains unclear how promising small-scale initiatives would be scaled up for whole population impact (Butland et al. 2007). […] NICE recommends that interventions to improve diet should be multicomponent (i.e. including dietary modification, targeted advice, family involvement and goal setting), tailored to the individual, provide ongoing support, include behaviour change strategies and include awareness raising promotional activities as part of a longer term, multicomponent intervention rather than a one off activity.”

“The Office for National Statistics (2003) reported that distances walked annually dropped by 63 miles between 1975 and 2003 [I was actually sort of surprised the number wasn’t higher…]. Similarly, distances cycled dropped by 16 miles in the same period [I must admit part of the reason why I picked out the quote was that I wanted to illustrate once again why I gave this book a low rating on goodreads; the book here clearly gives you the impression that people walk less and bicycle less than they used to do. But try to look at those numbers and divide each of them with 365. There’s no way in hell those 16 miles of bicycling *per year* per person makes any measurable difference on any semi-relevant health variable of interest – this is something like 40 meters per day per person, or 10 seconds of bicycling per day, assuming an average speed of 15 km/hour…]. The proportion of people who travel by walking or cycling has declined by 26 per cent (Department of Health, Physical Activity, Health Improvement and Prevention 2004). [This number on the other hand seems much more likely to have health-relevance. But then you immediately start asking yourself: if that number is true, why are the other numbers so low? And the inclusion of all of the above numbers in the coverage actually illustrates perfectly a recurring issue I had with the coverage; there are a lot of numbers here, and they don’t all tell the same story, and the authors aren’t always making it the least bit easier to make sense of them because they seem to treat many of them quite uncritically. Maybe fewer people cycle, but those that do put in more kilometers – but the authors aren’t suggesting this in the text, so you sort of need to come up with these sorts of explanations for the semi-weird constellation of research results yourself]. Consequently, it has been argued that active transport is a key factor in the achievement of healthy levels of physical activity […] All four national surveys demonstrate the same sex difference in activity levels. Physical activity is the only lifestyle behaviour where men are more likely to achieve government guidelines than women […]. Sport is a traditional male activity which may contribute to this finding.”

“The relationship between [physical] activity and social class as measured by the National Statistics Socio-Economic Classification (NS-SEC) […] is complex. […] The relationship between NS-SEC and physical activity can be described by an inverted U-shaped curve, with those at either end of the NS-SEC scale being the least likely to be active. […] Compared to the general population, South Asian and Chinese men and women were much less likely to participate in physical activity of any kind. Bangladeshi men and women were the most inactive and were almost twice as likely as the general population to be classified as sedentary. […] Physical activity reduces the risk of premature mortality for everyone, regardless of their age, sex or ethnicity […] In England, the Department of Health, Physical Activity, Health Improvement and Prevention (2004) has estimated that adults who are physically active have a 20–30 per cent reduced risk of premature death. Warburton et al. (2006) have suggested that a 50 per cent reduction in risk from death is possible for the physically fit. The effect of physical activity on health manifests itself by its influence on a wide range of diseases. In particular, people who are physically active can achieve up to a 50 per cent reduced risk of developing the major lifestyle diseases: coronary heart disease, stroke, diabetes and cancers […] not only do inactive people face shorter lives, but also they face poor quality of life in the years preceding death. While the relationship of physical activity to each disease is important in its own right, what makes physical activity so important is the strength of its effect over such a wide range of conditions. […] Associations with health are generally stronger for measured cardiorespiratory fitness than for reported physical activity […] but a self-reported physical activity is still convincingly associated with reduced mortality […]. In short, cardiorespiratory fitness will benefit health but levels of physical activity that may not be of an intensity to alter physical fitness parameters may still have health benefits. […] Obesity is the main visible sign of inactivity, yet obesity is just one of possibly 20 chronic diseases and disorders for which low activity levels are a known contributory factor. […] it is easier to influence the energy intake–output balance through diet than through activity […] The evidence suggests that for physical activity to have a significant effect on bodyweight and in particular on weight loss then 30 minutes of moderate activity for five days a week is unlikely to be a high enough level of activity.”

“Social cognition theory has identified self-efficacy and perceived behavioural control as key factors in the practice of healthy levels of physical activity, but at best such models can predict 50 per cent of the variation in physical activity […] Extensive evaluation of social cognition models’ ability to predict uptake of physical activity leads to the conclusion that a perception of the risks of non-activity and the benefits of activity for health has at best a small impact of overall variation in physical activity behaviour. […] Kahn et al. (2002) in their review of informational campaigns found no evidence that informational only media-based campaigns were effective, in line with the theoretically derived conclusion that attempts to inform people of the benefits and costs of activity and inactivity are unlikely to facilitate substantial changes in behaviour. Similarly, Ogilvie et al. (2004) found no evidence that informational campaigns to increase active transport were successful. […] Behavioural interventions are more likely to be at a small group or individual level of intervention. Kahn et al. (2002) found that individually adapted behavioural change programmes were effective in increasing physical activity levels. Ogilvie et al. (2004) found that targeted behavioural change programmes were the most effective way to promote walking and cycling. […] Many public health interventions to increase physical activity in the community are not individualised, do not recognise the role of psychological processes in effective behavioural change and are carried out by professionals with no psychological training”.