Furthermore, a biochemist Douglas Coleman (1970) pointed at behavioural problem in obesity, his research focused on satiety factor (The Guardian, January 2003). Moreover, Ethan Allen Sims, a physician at the University Of Vermont College Of Medicine looked at the differences in metabolic rates between those who were thin or fat in order to find out if it influenced their body frame. He conducted an experiment were twenty Vermont State Prison inmates were over-fed during two hundred days and remained physically inactive. The result showed that those who found it difficult to gain weight lost the gained weight without difficulty by going back to normal food intake. Those who easily gained weight during the feeding regime, found it difficult to loose weight when their food intake was back to normal. He pointed out at the energy intake and expenditure, which somehow the body is equipped with to balance the energy equilibrium, i.e. “homeostasis”. Those prisoners, who had obesity running in their families, seemed genetically predisposed to maintain homeostasis at a higher weight, than others with no cases of obesity in their families (The Guardian, January 2003). The social influence in this case played a significant role in exhibiting the inmates’ genetic inclination. More importantly, studies with monozygotic twins showed that there are significant similarities regarding the body mass index (BMI). These results supported the idea that biology plays an important role regarding human obesity.
According to Bouchord (1988) and Stunkard at al. (1986) “genetic predispositions, diverse health behaviours and individual food choices all contribute in varying degrees to the expression of the obese state” (cited in Capaldi, 2001, p 291). Furthermore, studies conducted with obese ob/ob mice showed the link between the ob gene and the production of leptin, i.e. discrete protein (Drewnoswki, in Capladi 2001). Leptin injected to obese mice resulted in weight loss as a consequence of declined appetite for food. Unfortunately, the same could not apply to humans; leptin deficiency was not a factor that influenced human obesity.
In order to try to explain the development of obesity, it is important to look at the interaction between genetic and environmental influences. What influences an over weight or obese person to choose a particular food for consumption? Cabanac and Duclaux (1970) argued that obese people are more sensible to olfactory, oral and visual cues of foods than those who are thin. Moreover, they pointed out at the importance of food palatability; supposedly obese people have increased liking for sweet foods and drinks, but Drewnowski’s (1986) findings did not support increases liking for sweet food and beverages in obese people (Capaldi, 2001). Moreover, he concluded that the preference for sweetness has nothing to do with the body weight. However, preference for sweet is in-born, but exposure to food without negative effect such as getting ill or nausea, would increase the preference for that food.
Furthermore, there are four factors which increase a food preference: mere exposure, the medicine effect, flavour-flavour learning and flavour-nutrient learning (Capaldi 2001). Studies on taste sensation with the human fetus showed that there is a preference for sweet, but the refusal for bitter (Liley, 1972). Moreover, salt and bitter taste sensations changed after birth onwards. Additionally, because of their mother’s food consumption, infants are exposed to variety of flavours through amniotic fluid in the womb, as well as through mother’s milk. Consequently, they might obtain certain preferences for food consumed by their mothers. Nevertheless, a further research in this field regarding later food preferences is needed (Manella & Beauchamp in Capaldi, 2001).
According to Capaldi (2001), experience influence food preferences in regard to later eating behaviour. Studies with humans showed increased salt consumption in later life, if a person was deprived of sodium at the early stage of life. Furthermore, Beauchamp and Moran (1985) found that infants who consumed sweetened water at the very early stage in life, showed increases preference for the same at the age of two, compared with the infants not exposed to sweetened water. More importantly, no increase preference was found for other sweet beverages or food (Capaldi 2001). Furthermore, people learn to prefer some flavours, if a flavour is related to sweetness it would become preferred. For example, coffee itself has an unpleasant and bitter taste, but taken with sugar and milk would become pleasant. Moreover, preference for nutritious food is also in-born; we have a predisposition to learn to preserve flavours that are associated with nutritious foods (Capaldi 2001). Capaldi et al. (1987) in their study showed that flavour-nutrient learning occurs independently of flavour learning. Rats prefer a flavour that was given to them in saccharine 30 minutes prior to lab feeding, than a flavour in saccharine when no food was given after (Capaldi 2001). People prefer food that is calorie consistent, therefore high-fat foods would be preferred to low-fat foods. Balles et al. (1981) study showed higher preference “for a flavour associated with two-grams of a four-calorie food, then for a flavour associated with four-grams of a two-calorie food” (cited in Capaldi, 2001, p 60).
Furthermore, food consumed under high deprivation would increase the preference for that food. Capaldi et al. (1991) reported that rats feeded with unsweetened food preferred the flavours that were exposed to under high deprivation, to food that were exposed to under low deprivation (Capaldi 2001). Foods which is consumed when we are hungry always seems pleasant and tasty, and the same food would remain pleasant if eaten even when we are not hungry, showing that there is a learned effect for food preference.
Another factor that influences eating behaviour in later life is the control of early experience of food intakes. The early experience shapes individual differences regarding foods preferences, styles and quantity of food intake. Moreover, learning is a fundamental factor regarding development of the control of food intakes. Their caregivers, i.e. the quantity and the quality of foods, the frequency and the interval between feedings, determine infants’ food intake. Fomon (1993) points out that feeding an infant on demand contributes to his or hers learning to link the start of a meal with the feeling of hunger and the end of a meal with the feeling of satiety. Nevertheless, when infants become young children, they quickly learn that food is not only associated with hunger, but also environmental and social influences play a major role in food consumption (Birch and Fisher in Capaldi, 2001). Doris (1939) in her experiment showed that infants somehow have an ability to self select a healthy diet, adjusting a meal size according to the calorie consistency of consumed foods, but the same does not apply to eating behaviour of adults. Rolls (1986) pointed out that what influences the quantity of consumed foods is the variety of available food, more palatable foods available, larger consumption would occur (Birch and Fisher in Capaldi, 2001). Johnson and Birch (1994) proposed that parents’ eating style influenced their children’s eating behaviour and regulation of energy intake. They suggested that these early differences in regulation in energy intake influenced differenced in later eating habits and calorie intake (Birch and Fisher in Capaldi, 2001).
Moreover, young children reject initially unfamiliar food and their food selection and preference is associated with learning. Fisher and Birch (1995) showed that children’s diet together with the type of food they eat are the result of their preference. Children who prefer high-fat foods selected this type of food for consumption, high percentage of their calorie intake was from high-fat foods and their parents were the heaviest (Birch and Fisher in Capaldi, 2001). These results indicate the importance of family regarding the children’s food selection and their eating habits.
Furthermore, socio cultural factors certainly play an important role in food selection and quantity of food intake; when, how much and what is consumed is determined by cultural influences. Cultural differences in food selection are tremendous, what is regarded as desirable and “appropriate” to eat in Japan would not apply in Germany. The availability and food choice is strongly influenced by socio-cultural factors, i.e. indirect and direct social factors. Culture-specific cuisine would have a strong influence in food we choose to eat, religion, believes and attitudes would guide our eating behaviour, and exposure, cost and the context within which a food is attended also influences our consumption (Rozin in Capaldi, 2001). We often classified food as liked and preferred or dislike and even disgusting. In some cultures is important who prepares the food and if prepared by “inappropriate” person the food would be rejected. For example, Hindu Indians’ caste structure regulates who is allowed to prepare food for whom, who can serve it to whom and even who can eat whose leftovers. According to Appadurai (1981) “ among Hindu Indians, a food’s personal history carries social status and moral significance” (cited in Rozin, in Capaldi, 2001, p 246). Disgust is usually linked with contagion, and the stimuli that evoke it are culturally influenced and specific. Western people would not touch a food, which was contagious by mice, a fly or a cochroach, we would find it disgusting, unhealthy and absolutely unacceptable for consumption. Moreover, among Hindu Indians the moral aspect is more important in regard to disgust and contagion than physical aspect. Furthermore, issues of moral values also influence our food choice and they are usually transferred from parents to children (Cavalli-Sforza, 1982 & Rozin, 1991).
There is increasing number of Vegetarians, whose eating behaviours are influenced either by health moral-ecological factors. With the increase of moral vegetarianism meet consumption becomes a question of values rather than an issue of preference (Rozin in Capaldi, 2001).
Furthermore, the environment in which we live also influences our eating behaviour and food choice. Living in a busy society means to do as much as possible in the shortest possible time, we do not cook anymore and our culture is transforming into a fast-food culture. The advertising for McDonalds, Burger King and many other fast-food companies is associated with the happy events, families gather and happily shared burger and fries giving a message –don’t waste your time on cooking, have some “quality” time together. Fast food is practical, tasty, cheap and available on each step. Advertising sweets, salty and fatty foods are good business, tempting children with free toys and other gadgets in children meals, making them a vulnerable target of advertising. Childhood obesity increased rapidly over years and became one of the top issues of our time. The UK spends £25 billion a year on fast food, food that is addictive and the cause of many diseases including diabetes and heart diseases, because of their high concentration of salt, sugar and fat (Vale, 2002).
Huston, Texas is known as America’s fattest city with the highest rate of obesity in the USA, 30 per cent of school children are overweight, almost double than in the UK. In Texas everything revolves around eating, they say “Bigger is better”, the choice of food is enormous, portions are enormous and many restaurant even use a tactic “If you can eat it- it’s free” to tempt customers to higher spendage giving them a “value for money”. Moreover, 33 billion dollars goes to Weight Watchers, while the weight loss surgeries increased 50 per cent from the last year’s figures in the USA. Insurance companies are concerned if it is more cost-effective to leave people fat or to make them thin with a weight loss surgery, is it more profitable to pay for a heart attack or a cardio-vascular decease as a consequence of obesity, or to pay up to 30 thousand dollars for a weight loss surgery although it carries a big risk (America’s Fattest City, Channel 4, Granada TV, January 2004).
Currently in the UK the government intervenes in Britain’s obesity crisis, investing £2 million in a program to fight obesity. By involving and educating families how to pack children’s lunch boxes, by banning crisps and chocolates from schools and replacing them with healthy food, they hope that obesity increase would stop among school children. Nonetheless, economy is a strong force and companies that make profits out of obesity epidemic would not give up easily.
People’s eating behaviour is influenced by genetics, but genetic predisposition alone cannot be accounted for a cause of obesity. Diets and life styles habits, food preference, early experience of the control of food intake and socio-cultural factors all shape our eating behaviour. Unfortunately, there is no a “magic pill” which helps to loose weight and maintain it, and certainly the notion of the “set point” does not encourage an easy weight loss, therefore, we are left again with “eat less-exercise more” or change your “food brand”, which is not easy, but obviously for now the only way to healthy life without excess weight.
References
Capaldi, E.D. (2001) Why We Eat What We Eat: The Psychology of Eating. Washington: American Psychological Association.
Vale, J. (2002) Slim For Life: Freedom from the food trap. London: Thorsons.
http://www.guardian.co.uk/business/story. Fat is financial issue. December, 2002.
http://www.guardian.co.uk/weekend/story. Born to be fat. January, 2003.
http://observer.guardian.co.uk/review/story. The politics of thin. January, 2003.
http://observer.guardian.co.uk/foodmonthly/story. Are we turning our children into “fat” junkies? October, 2003.
http://www.emedicinehealth.com/fulltext. Obesity. January, 2004.
http://www.txtwriter.com/Onscience/Articles/faddiets.html. January, 2004.