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'Indulgence' or 'functional'? The role of sweet foods
"Indulgence" or "functional"? The role of sweet foods
Nutritionists in industry, who represent the nutrition interests of the UK's leading food and drink companies, recently hosted a conference on the role of indulgence foods in a healthy lifestyle. The half-day programme featured some of the UK's leading scientists and provided valuable insights to both marketing and consumers' attitudes alongside the latest scientific understanding of food and health.
Consumer attitudes to the UK food and grocery industry
Dr Richard Hutchins, Business Manager, Institute of Grocery Distribution (IGD), gave a stimulating account of extensive (qualitative and quantitative) research conducted by the IGD in the summer of 1999. Amusingly, he revealed that consumers might be placed into four distinct groups based on their views of the UK grocery industry:
Delighted Delia: the contented consumers (1 in 3 people);
Fastidious Flora: seeks out vegetarian foods and non-allergenic foods (1 in 14 people);
Cynical Simon(e): price conscious shopper (1 in 4 people); and
Carefree Colin: a non-shopper with little interest in food (1 in 3 people).
Hutchins believes that a key challenge for the grocery industry today is to ensure that consumers have access to balanced and accurate information, and to avoid "information overload" by ensuring that they receive information relevant to them as an individual, not the whole population. Changes made by the food industry must benefit the consumer and this benefit must be communicated to the consumer. Customers need to know how profits are made and used (new product development, improved efficiency, etc.) and companies should attempt to illustrate the benefits of science.
As one consumer put it, "We are probably lucky - we just don't feel it".
Sugar, fat and obesity: is there a link?
Obesity is one of the most pressing public health problems in the UK. Today almost 60 per cent of the adult population are overweight and the proportion of people who are obese has increased from 6 and 8 per cent in men and women respectively in 1980 to 17 and 20 per cent in 1997. Dr Susan A. Jebb, MRC Human Nutrition Research, Cambridge, tackled the controversial issue as to what makes us fat and to what extent, if at all, we can blame it on over consumption of the so called "indulgence foods".
Jebb comments that in recent years the simplistic view that obesity is the inevitable consequence of excessive consumption, especially of "indulgence" foods, has been challenged. Average energy intakes in the UK have actually declined over the last 30 years, whilst obesity has increased sharply. This implies that there have been even greater reductions in energy needs.
Today, scientists are showing a greater interest in physical activity and studies are accumulating which suggest that low levels of physical activity may be underpinning the epidemic of obesity. Those who do exercise regularly tend to have a higher energy intake than the remainder of the population and yet are less likely to be obese.
However, Dr Jebb warns that dietary factors cannot be disregarded. Although energy intakes have fallen there has been a sharp rise in the proportion of fat in the diet at the expense of carbohydrate. Epidemiological studies show that individuals within a population who consume the greatest proportion of their energy as fat are at the greatest risk of being obese. However, analysis of the 1986-1987 Nutritional Survey of Adults found no evidence that those consuming the greatest quantity of the "indulgence" foods were more likely to be obese. In women there was no association and in men those in the group consuming the most "indulgence" foods tended to be lighter than those consuming the least.
Dr Jebb outlined more detailed experimental studies, which provide some clues about the control processes that regulate body weight. Jebb believes that the energy density of a food is key. Individuals allowed to eat freely tend to gain weight when food is rich in fat, relative to food rich in carbohydrate. This effect seems to occur because fat is so energy dense, providing twice as many calories gram for gram as protein or carbohydrate. This inadvertent consumption of excess energy from energy-dense foods is known as "passive over-consumption". Low fat foods, which have a lower energy density to their full-fat equivalents, e.g. reduced-fat milks, may therefore reduce the risk of weight gain, but the role of low-fat products with similar energy density to their full fat counterparts is less clear and more research is needed.
Dr Jebb concludes that any food that is eaten in excess of energy needs will lead to weight gain, but the chances of gaining weight cannot be explained by differences in the consumption of "indulgence" foods alone. Other aspects of eating behaviour and the broader lifestyle may be equally as important in determining the risk of obesity in individual subjects.
The role of carbohydrate foods in an active lifestyle
The presentation by Professor Clyde Williams, Sport Science, Loughborough University, focused on the athlete and the challenge to nutrition to provide sufficient carbohydrate to sustain heavy prolonged exercise, especially for people who daily undertake heavy exercise.
The body's two main fuels are fat (stored in adipose tissue) and carbohydrate (stored as glycogen in liver and in skeletal muscle). Glycogen stores represent only 2 per cent of the energy stored as fat and yet as exercise intensity increases so carbohydrate rather than fat becomes the dominant fuel.
One of the main reasons for the differences in the contributions of fat and carbohydrate to energy metabolism, as exercise intensity increases, is the rate at which they can be converted to the "energy currency of life" namely adenosine triphosphate (ATP). More ATP is derived from a molecule of fat than from carbohydrate; however, the rate of ATP production is faster when carbohydrate is the fuel. Fat metabolism is entirely dependent on aerobic metabolism (and the presence of carbohydrate) whereas carbohydrate can be converted to ATP with and without a high rate of oxygen delivery. Thus during exercise of moderate intensity fat can often provide an equivalent amount of energy as carbohydrate to muscle metabolism.
However, as exercise continues, the stores of carbohydrate are reduced to critically low values so much so that the rate of ATP production cannot be supported by fat metabolism alone. The consequence of this reduction or depletion of muscle glycogen is the onset of fatigue and this occurs in the presence of an abundance of potential energy stored in our fat cells. Even at lower exercise intensities when there is a greater contribution from fat to energy production, fatigue occurs when muscle and liver glycogen stores are reduced to critically low values.
Therefore, recognizing the need for carbohydrate, snacking strategies need to be developed in order to ensure that exercise performance is not compromised because of inadequate pre-exercise liver and muscle glycogen stores. Professor Williams outlined recommendations for the amount and type of carbohydrate to be consumed in the three critical phases - before, during and recovery from exercise.
Is snacking beneficial?
Many of us are guilty of a specific pattern of eating, commonly known as snacking, but is this behaviour beneficial, hazardous or benign? This was the fascinating subject covered by Professor John Blundell Chair of PsychoBiology, University of Leeds.
Blundell acknowledges that the degree of "snacking" is difficult to determine and rests upon the criteria for distinguishing meals from snacks; this involves features of size, duration, timing and composition of foods eaten. Frequency of snack consumption can range from one to seven with an average of about 2.3 snacks per day. In regular snackers the food consumed can account for up to 25 per cent of the total daily energy intake.
The key question then is what are the effects of snacking on appetite control, energy balance, weight gain, metabolic profiles, and indices of health. According to Blundell, the possible benefits of snacking could be reflected in physiological or psychological end-points. The evidence suggests that distributing the total day's food intake into a large number of small episodes (as opposed to the small number of large episodes) may give rise to favourable blood glucose metabolism and may result in reduced plasma LDL cholesterol. In addition, contrary to popular belief, when snacks are voluntarily consumed this pattern of eating does not lead to over-eating or weight gain.
Much more important than the frequency of snacking is the nutrient composition of the snacks. High fat snacks can lead to an augmentation of total daily fat intake, whereas low fat snacks reduce daily fat consumption down to a level recommended by national guidelines. Blundell states that:
this may mean that free consumption of high carbohydrate/low fat snacks can effectively control appetite, prevent over-consumption and prevent weight gain.
In addition to the impact on nutritional well being, snacks can deliver energy to prevent hunger becoming a distracting sensation. A snack intake in the late afternoon has been shown to have positive effects on mental performance involving sustained attention or memory. Survey data indicate that people have a positive view of snacks, which can provide relief from hunger, maintaining a balanced diet, relieving stress/tension and helping concentration.
Diet and dental caries - a relationship re-examined
A meeting based on the consumption of sweet foods cannot fail to include the issue of dental caries since sugar has long been regarded as the "arch criminal" for the causation of dental caries.
However in his presentation Professor Duggal, Paediatric Dentistry, Leeds Dental Institute, points out that in most Western countries there has been a dramatic decline in the dental caries prevalence. This has occurred in most cases in spite of no change in the consumption of refined carbohydrates in the form of confectionery and soft drinks. Instead what has happened is that in many countries the distribution of dental caries has become "bimodal", with 80 per cent of the disease present in only 20 per cent of the population.
Consequently, Duggal believes there should be a shift in the emphasis for providing preventive advice for the general population to "targeted intervention". Those who are "high caries risk" should be targeted and the mainstay of preventive measures are the judicious use of fluoride, plaque control, fissure sealants and a sensible diet. This should be aimed at reducing the frequency of consumption of acidogenic and cariogenic foods should be formulated for those children who are prone to caries.
Duggal's key advice to keep children's teeth healthy is:
enjoy three substantial meals per day;
sweet drinks must only be consumed with meals;
between meals, drinks should be milk or water;
do not drink for at least one hour before bed and never during the night;
sweet confectionery should be eaten at mealtimes and no more than two snacks per day; and
clean teeth twice a day.
Food craving and addiction all in the mind?
Peter J. Rogers, Department of Experimental Psychology, University of Bristol, focused on chocolate which is the food most frequently associated with reports of food craving and "addiction". The basis for this belief is the presence of psychoactive substances (e.g. caffeine, theobromine, phenylethylamine, tryptophan, magnesium and anandamide) in cocoa-containing products. However, after extensive reviews by Rogers, of what is known about the concentrations of such substances in popular chocolate confectionery and their probable effects on the brain when administered orally, he was unable to find any convincing support for such speculations.
Another hypothesis is that some foods are craved because their high carbohydrate content can increase brain serotonin neurotransmission and thereby improve mood. This, though, is also unlikely to be relevant to chocolate and chocolate products, because they contain sufficient amounts of protein to counteract the claimed effects of carbohydrate on brain serotonin.
Similar problems exist for ideas relating mood and food craving to effects on endogenous opioids, and to biological explanations of pre-menstrual food craving. Rogers concludes that it is far more plausible that liking for chocolate, and its effects on mood, are due mainly to its principal constituents sugar and fat and their related oro-sensory effects.
If there is no good reason to conclude that chocolate produces the critical biological effects which underlie addiction and substance abuse, why do some people claim to crave chocolate and even to be addicted to it (e.g. "chocoholics")? Roger's answer to this question is that food craving and self-reported food addiction can be best understood in relation to the cognitive control of eating. This does not mean that the biological effects of eating are unimportant, but merely that these form only part of the determinants of human eating behaviour and the experiences accompanying eating.
Against this background of the biological and cognitive processes controlling appetite, Rogers suggests that it is ambivalence ("nice but naughty") about certain foods and the resulting attempts to resist eating them that are the basis of self-reported food craving and food addiction. The ambivalence about chocolate arises from the attitude that while this is a highly palatable food, it is not a staple component of the diet but instead a "treat" that should be eaten with restraint.
However, attempts to restrict intake only cause the desire for chocolate to become much more prominent and intense, and this experience is then labelled as a craving. This, together with the need to provide a reason for why resisting eating chocolate is difficult and sometimes fails, can then lead the individual to an explanation in terms of addiction (e.g. "chocoholism"). According to this "bio-psycho-social" explanation, chocolate is the most frequently craved food because it is the food that people most often try to resist eating. In contrast to craving, moreishness ("causing a desire for more") occurs during rather than preceding an eating episode. Nevertheless, restraint is again an essential feature, because moreishness is experienced when the eater attempts to limit consumption before the appetite for the food has been satiated.
Why people buy - the psychology of chocolate and biscuit consumption
Peter Cooper, chartered psychologist, CRAM International, presented some insights about the popularity of foods such as cakes, biscuits and confectionery and why they are perceived to be an indulgence.
Key findings from Cooper's extensive research (monitored over time by population demographics and psychographics throughout Europe) into food consumption habits, attitudes and motivations, included the following consumer beliefs:
the type of food eaten is believed to be the number one factor affecting health;
Three out of four Europeans claim to be interested in nutritional information; and
nearly 60 per cent believe their current diet is healthy but over half want to be slimmer.
Cooper points out there is clearly evidence of conflict between what people think, believe and say they do with what they actually do. For example, sweet food consumption is typically underestimated and clearly in terms of eating behaviour consumers wish to appear rational and in control.
Sweet food eating behaviour strongly reflects local traditions such as social codes, cultural, religious and philosophical values. Northern European and US consumers' beliefs about food emphasise function, and information driven rationality with the focus on self help and disease prevention. Sugar is perceived as "bad for you". However, in reality, their confectionery consumption is very high.
By contrast, in southern Europe, consumers are more moderate consumers of confectionery and in terms of eating behaviour they emphasise pleasure and a holistic balance - no food is good or bad and family "ritual" meals are very important.
As Cooper points out there are rational arguments in favour of indulgence foods. Most nutritionists accept that they can be healthy for you in moderation and less bad than perceived. However, Cooper believes these rational arguments to be like rhetoric to the consumer - persuasive and prompting questions about honesty and creditability. Or they can actually undermine the pleasure of sweet foods. They do not confront the deep moral objections to sweet foods and do not accept the rich psychology of food and eating behaviour.
Julie DeanNutrition Consultant