So what is going on?  Weight gain is not a mystery.  Fat does not materialise out of nowhere. Obesity can only be explained in terms of an imbalance of energy consumption over energy expenditure. Fat people are eating too much and not exercising enough.  It’s all down, so cynics assert, to a combination of gluttony and sloth, a gross demonstration of moral failure.  But is that a fair indictment?  Some people may have a genetic tendency to put on weight; after all, the biggest risk factor for obesity is having parents who are overweight or obese.  The idea that a pre-history of starvation might have selected a thrifty gene was currency until very recently, through we now know that the way we conserve energy is under the control of several different genes.  

And there is also an environmental issue. The Foresight Report, published in 2007, declared that obesity is a normal response to an abnormal social environment. The watchword is convenience. People in the west are money rich and time poor.  There is always too much to do.  Time must not be wasted.  We eat fast food and get around in fast cars, trains and planes. Time spent on cooking, the cost of food, buying local food, growing our own food have all decreased.  Fewer people grow their own vegetables or buy local produce. We have become disconnected from food.production and preparation in the same way as we are uncoupled from the use of our own legs to get around. Fewer people are walking or cycling to work.  Children are taken to school by car. And fewer people engage in energetic sports or activities.  On the other hand, the availability of fast food outlets, low cost bistros and restaurants, food variety, food promotion and portion sizes have all increased alongside the ownership of cars and improvement in public transport.  In fact, less and less people need to go to work any more. They can just plug into their virtual Microsoft office and stay at home. We are rather like the cafeteria rats, who, when confined to their cages and fed a varied, appetizing diet in abundance, grow enormously fat.    

This fast food, car based revolution has given licence for passive overconsumption and immobility. With too many opportunities to eat and less requirement for physical activity, people cannot help but gain weight, or so it seems.  Fast, convenience food is cheap and rich in fat.  Restaurants tend to serve big portions of high fat foods. And people tend to eat what is put on their plates. One experiment showed that when soup was presented in a bottomless, refillable bowl, people just kept eating.   Time that might be spent in physical activity is all too readily plundered by the computer and television.  The exhausted boredom, induced by the tedious combination of overstimulation and inertia can tend to cause people to seek solace in comfort eating. 

But if it was just the environment that was responsible for the obesity epidemic, then why aren’t we all fat.  80% of adults living in an obesogenic social environment are not obese and 40% are not even overweight. 

Take the French, for example; they traditionally eat a diet that is so high in cholesterol and fat and yet have less heart disease and obesity.  The most obvious explanation is  portion size.  Dr Paul Rozin in a recent article entitled ‘The Ecology of Eating’ showed that portion sizes for the same meals were 25% per cent larger in the United States than in France. Barbara Rolls showed that increasing portion sizes over the course of a week increased energy intake by 4,500 Cals, equivalent to 1.5 Kg of fat.  Increasing the consumption of fat resets physiological satiety mechanisms, so that more fat can be accommodated and people want to eat the same high fat meal again. People often notice a marked increase in appetite and weight after the annual Christmas blow-out.  The opposite works after starvation; fat receptors can be up or down-regulated. Exercise is good because it blunts this desensitisation and hunger.

The way food is served, the availability, variety, portion size and even the shape of plates all have a role in increasing intake.  We eat more when food is prepared by someone else. If we are eating with others, we tend to conform to the norm.  Food outlets tend to serve the most enormous portions.  They give too much choice and choice is inimicable to regulation.  When people are presented with a meal containing a variety of foods, they will eat much more than if they are given limitless quantities of the same food. 

So the answer to preventing obesity seems so easy.  If it is just a matter of the environment, then all you have to do is alter your personal environment.  Eat less,  cut down on portion sizes, choose low fat foods, don’t have seconds, don’t eat between meals, ration chocolate and alcohol, cook at home, only eat meat twice a week, cut down on butter, pastry, don’t rely on public transport so much, walk, cycle, take regular exercise. Take control of your life. Go on a diet.  Put yourself on an exercise regime.  About 70% of women and 30% of men claim to be on weight reducing diet. So why for most, doesn’t it work? 

Twenty years ago, the journalist, Geoffrey Cannon, published his eye catching title, ‘Dieting makes you fat’.  His thesis might be explained in part by the facts that it is fat people who tend to diet and it is very difficult to lose weight by dieting.  But there is another factor; if you deprive somebody of something you will increase the desire for it, and when they are let off the hook, they will rapidly eat more. Dieters tend to crave food and the foods they crave the most are those that they are trying to resist. 

Disinhibited eating is enhanced by the last supper effect (I’ll just have one more chocolate, then I’ll stop) and the what the hell effect, (oh, now I’ve had sticky toffee pudding, I may as well have another portion),  as well as by alcohol consumption,  eating alone, the behaviour of co-diner, and negative mood.  Dieting is more difficult when people are under an increased emotional load and feel brittle. The hedonic tendency to eat between meals might indicate an insecurity that demands satisfaction through the most basic source. Walking on the moors in late spring, I notice how lambs rush to their ewes to suckle as soon as I approach. Is that an example of the same insecurity?   

The overwhelming temptation to break one’s diet is an illustration of what psychologists call, ‘Wegeners White Bear Effect’.  The more you try to suppress any thoughts about something, the more you will tend to think about it, which results in a rebound in the behaviour you are trying to suppress.  Suppression can make people exquisitely sensitive to environmental cues.  The eponymous heroine in the novel,  Leila’s Feast, illustrates how starvation can make somebody very aware of food.  Leila wrote her cookery book while she was starving in a Japanese prisoner of war camp. A recent UK survey showed that people tended to think about eating 200 times a day.  This might suggest that they were exerting a tight control on their eating behaviour, which would just enhance the craving for food. 

You have to devote time and thought to cooking healthy meals. It takes too much work to exercise.  It’s all too hard, especially if you are doing it against such a resistance.  In the past, if we didn’t work, we would starve. Now our eating has become uncoupled from the production  and preparation of food. We don’t need to work to get our meals, so why should we?  If food is there, why not eat it?  So perhaps human nature hasn’t changed that much, we may have always tended to be lazy and greedy.

But this still doesn’t explain why we aren’t all fat.  Maybe it’s all down to the culture of eating.  The French eat less but spend more time eating.  They make more of an occasion out of eating; the ambience is different.  The French tend to eat together.  A meal serves more functions that just the supply of energy.  Eating is part of a whole sequence of social grooming.  Eating together with family and friends provides relaxation, companionship, comfort and reassurance. A family that eats together tends to stay together. One in five families in the UK sit down to eat together only once or less than once a week. Many people in the United States or in Britain eat alone and can miss out on the social benefits of mealtimes and so may consume extra large portions to compensate for a degree of social deprivation.

So is overeating related to deprivation?  It is well known that people who have been subjected to starvation tend to stockpile food, eat up every last morsel and overfeed their children. Population studies have shown a definite link between poverty and obesity, but not all poor people get fat. The historian, Peter Brears, suggested that working mothers lose the skill and the time to prepare meals and tend to rely more on convenience food, rich in fat. In the Foresight report the only group who are less likely to become obese are reasonably affluent women living in the south east of England who have the time to keep fit and choose healthy dietary options. 

But since mealtimes are a whole nurturing experience rather than just a nourishing experience, is eating a surrogate for other types of deprivation?  Does the loneliness and depression that is also so prevalent in the United States and Britain, make them more likely to turn to food for comfort and solace?  People who don’t actively engage in life get bored and eat to feed their interest and confidence rather than their body.  When I conducted psychological interviews on patients with morbid obesity, I uncovered a severe degree of loneliness, depression and emotional deprivation.  So is there a typical obese personality; insecure, needy, bored and chaotic, the sort of person who might tend to turn to drugs, alcohol, cigarettes, love and companionship as well as food to satisfy their compulsive needs?  When something happens, a person’s ability to regulate their food intake gets disturbed alongside regulation of other behaviours, sleep, mood and bowel habit, for example.  There are super-regulators, who intensify their control and tend to lose weight and others, who are perhaps more chaotic and needy, who become dysregulated and obese. So do food manufacturers and restauranteurs just supply what is needed so badly? 

A recent report suggested that the tendency of people to use food to satisfy their emotional needs may be gender specific. The psychologist, David Lewis, was recently reported as saying that when it comes to tongues, melting chocolate better than passionate kissing, at least for women. All men know that sex is better than chocolate; for women it’s the other way round..

So have psychological factors, such as life traumas, deprivation, need, loneliness and depression, which seem to have increased over the same period impacted with the environmental changes to create the current obesity epidemic?  And how much of a role  do genetic factors play?   

The current obesity epidemic is such a complex mix of mind, body and meaning with culture, history and development each playing their part. There is no easy explanation, though the interaction of the loneliness, boredom and insecurity of modern life with the abundance of cheap high energy foods and the reduced requirement for physical work seem to be essential drivers.

So how can we remain slim and healthy in an obesogenic environment?  Maybe the answer is to dare to stand out from the crowd and adopt an active, healthy and interesting life style where eating is not a predominant factor.  Children, who go on the fat camps run by Dr Paul Gately, lose weight as they gain in self esteem.  So the message is don’t rely on dieting; this is almost like treating deprivation with deprivation. Don’t necessarily diet (though you may just watch your weight), but get out there, do things, be active, get involved and maybe, just maybe, you can allow your weight to look after itself just fine.   

This article was inspired by a talk delivered by Andrew Hill, Leeds Professor of Health Psychology, to the Guilds of Food and Health Writers at their joint meeting at Artisan, Booth’s bistro in Kendal, Cumbria. 

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1. Wells, A.S., Read, N.W., Craig, A. Influences of dietary and intraduodenal lipids on alertness, mood and sustained concentration. British Journal of Nutrition 1995; 74: 115-123.
2. Wells, A.S., Read, N.W. Influences of fat, energy and time of day on mood and performance. Physiology & Behaviour 1996; 59: 1069-1076.
3. Wells AS, Read, NW, Uvnas Moberg K, Asler P. Influences of fat and carbohydrate on postprandial sleepiness, mood and humour. Physiology and Behaviour l997; 6l (5): 679-686.
4. Wells AS, Read NW, Laugharne J, Athluwalia NS. Alterations to mood after changing to a low fat diet. B.J. Nutr. l998; 79: 23-30.
5. Wells AS, Read, NW, Idzikowski C. Jones J. Effect of meal on objective and subjective measures of daytime sleepiness. Am. J. Applied Physiology. 1998; 84 (2); 507-515
6. Wells AS, Read NW, MacDonald I. (l997) The effect of carbohydrate and lipid on resting energy expenditure, heart rate, sleepiness and mood. Physiology and Behaviour 1998; 63 (4): 621-628.
7. Zmarzty SA, Wells AS, Read NW. The influence of food on pain perception in healthy human volunteers. Physiology and Behaviour 1997; 62 (l):185-191.
8. Zmarzty SA, Read NW. (1999) An examination of isoenergetic intragastric infusions of pure macronutrients on cold pain perception in healthy human volunteers. Physiology and Behaviour. 1999; 65(4):643-648.

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1. Welch, I.McL., Saunders, K. and Read, N.W. The effect of ileal and intravenous infusions of fat emulsions on feeding and satiety in human volunteers. Gastroenterology.1985; 89: 1293-1297.
2. Welch, McL.I., Sepple, C., Read, N.W. Comparisons of the effects on satiety and eating behaviour of infusion of lipid into the different regions of the small intestine. Gut. 1988; 29: 306-311.
3. Sepple, C.P., Read, N.W. Gastrointestinal correlates of the development of hunger in man. Appetite 1989; 13: 183-191.
4. French, S.J., Murray, B., Rumsey, R.D.E., Sepple, C.P., Read, N.W. Preliminary studies on the gastrointestinal responses to fatty meals in obese people. Int. J. Obesity 1993; 17: 295-300.
5. Read, N.W., French, S.F., Cunningham, K. The role of the gut in regulating food intake in man. Nutrition Reviews 1994; 52(1): 1-10.
6. French, S.J., Bergin, A., Sepple, C.P., Read, N.W., Rovati, L. The effects of loxiglumide on food intake in normal weight volunteers. Int. J. Obesity 1994; 18: 738-741.
7. French S.J., Murray B, Rumsey, R.D.E., Fadzlin, R., Sepple, C.P., Read NW. Adaptation to high fat diets: effects on food intake and plasma cholecystokinin. Brit. J. Nutr. 1995; 73: 179-189.
8. Cecil JE, Castiglione K, French SJ, Francis J, Read NW. Effects of intragastric infusions of fat and carbohydrate on appetite ratings and food intake from a test meal. Appetite. 1998; 30: 65-77.
9. Cecil JE, Francis J, Read NW. Relative contributions of intestinal, gastric, orosensory and informational influences to changes in appetite induced by the same liquid meal. Appetite. l998; 3l (3): 377-390.

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1. Khan, M.I., Read, N.W., Grundy, D. (1993) The effect of varying the rate and pattern of gastric distension upon its sensory perception and motor activity. Am. J. Physiology. 264: G824 –G827.
2. Barbera, R., Feinle, C., Read, N.W. (1995) Abnormal sensitivity to duodenal lipid infusion in patients with functional dyspepsia. Europ.J.Gastro. Hep. 7 (11):1051-7.
3. Feinle, C., Grundy, D., Read, N.W. (1995) Fat increases vection induced nausea independent of any changes in gastric emptying. Physiol Behav. 58(6):1159-65.
4. Barbera, R., Feinle, C., Read, N.W. (1995) Nutrient Specific Modulation of Gastric Mechanosensitivity in patients with functional dyspepsia. American Journal of Physiology. Digestive Diseases & Sciences. 40: 1636-1076.
5. Feinle, C., D’Amato, M., Read, N.W. (1996) Cholecystokinin-A receptors modulate gastric sensory & motor responses to gastric distention & duodenal lipids. Gastroenterology. 110: 1379-1385.
6. Feinle C, Read NW. (1996) Ondansetron reduces nausea induced by gastro duodenal stimulation without changing gastric motility. Am. J. Physiol. 271: G59l – 597
7. Read N.W., Freitag B, Abitbol JL. (l997) Efficacy and safety of the peripheral kappa agonist, fedotozine, versus placebo in the treatment of functional dyspepsia. Gut 4l: 664 – 668
8. Read N.W. (1999). Functional Dyspepsia: a case of indecision. Gastroenterology (editorial). 116 (3):515 – 520.

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1. McFarlane, A., Pooley, L., Welch, I.McL., Rumsey, R.D.E. and Read, N.W. (1986) How does dietary lipid lower blood alcohol levels? Gut 27: 15-18.
2. Read, N.W., Welch, I.McL., Austen, C.J., Barnish, C., Bartlett, C.E., Baxter, A.J., Brown, C., Compton, M.E., Hume, K.E., Storie, I. and Worlding, J. (1986) Swallowing food without chewing. A simple way to reduce postprandial glycaemia. Br. J. Nutr. 55: 43-47
3. Welch, I.McL., Bruce, C., Hill, S.E., Read, N.W. (1987) Duodenal and ileal lipid suppresses postprandial blood glucose and insulin responses in man: possible implications for the dietary management of diabetes mellitus. Clin. Sci. Mol. Med. 72: 209-216.
4. Welch, I.McL., Cunningham, K.M., Read, N.W. (1988) Regulation of Gastric Emptying by Ileal Nutrients in Humans. Gastroenterology 94: 401-404.
5. Eyre-Brook, I., Read, N.W., Brownson, J., Johnson, A.G. (1988) Influence of intraduodenal chenodeoxycholic acid on fasting secretory and pressure activity in the stomach and duodenum. J. Gastroenterol. Hepatol. 3: 557-563.
6. Read, N.W., Houghton, L.A. (1989) Gastric emptying. In; Motility Disorders, Ed. A. Ouyang, Gastroenterol. Clin. N. America 18: 359.
7. Cunningham, K., Read, N.W (1989). The effect of incorporating fat into different components of a meal on gastric emptying and postprandial blood glucose and insulin responses. British Journal of Nutrition; 61(2): 285-290.
8. Houghton, L.A., Kerrigan, D., Read, N.W. (1990) Effect of intraduodenal infusion of acid on the antro-pyloroduodenal motor unit in human volunteers. J. GI Motility 2 (3): 202-208.
9. Houghton, L.A., Mangnall, Y.F., Read, N.W. (1990) Effect of incorporating fat into a liquid test meal on the relation between intragastric distribution and gastric emptying in human volunteers. Gut 31: 1226-1229.
10. Cunningham, K.M., Daly, J., Horowitz, M., Read, N.W. (1991) Gastrointestinal adaptation to diets of differing fat composition in human volunteers. Gut 32: 483-486.

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