SNACKING
OBJECTIVE NUTRITION n°66 (November 2002)
By Matty Chiva
University Paris X - Nanterre - France

An old phenomenon, snacking is spreading in the developed world at the same time the food supply and lifestyle changes are increasing.  According to some, this habit may not have any specific effect on health so long as total energy intake remains within standard values.  For others, snacking may sometimes be the cause of meal destructuring along with a nutritional imbalance.  Regardless of this, the social, cultural or even personal origins of snacking are such that it would be difficult for the "snacker" to perceive snacking as separate eating, fully within the daily energy balance.  This is its main danger.

As the subject of a current debate on population health, snacking concerns as many health care practitioners and health care professionals involved in prevention as it does food and agricultural industry and consumers.  Whenever the choice of foods is diversified, snacking occurs.  Epidemiological data concerning the impact of snacking on health continues to be rare, and currently there are more opinions about it than established facts.

Snacking: a few fad?

Historians, ethnologists and sociologists emphasize the fact that snacking has a long history, going back to prehistorical times.  It differs according to different cultures.  Thus we currently find societies in which eating patterns totally exclude meals at fixed times and eaten in the company of others (Tonga Islands) and others where snacking coexists with structured meals (eating outside of meals, at any time, is known in Vietnam as "an choi," i.e., "eating to have fun").  It is especially widespread throughout southeast Asia when conditions permit it.  Snacking may be found in Mediterranean civilizations, for example tapas in Spain or mezzés in the Near East and in North Africa: small portions of various hors d'oeuvres, served with a cocktail, separated from the meal by an interval of time.  Snacking is also widely practiced in North America.

In developed societies, snacking goes hand in hand with economic development, overabundance of food, the continuous availability of food and its decreased cost.  It also accompanies changes in lifestyle, an increase in food eaten outside the home, as well as profound changes in cultural, moral and identity values and standards.  Snacking is not a new fad: rather it is the type of snack foods eaten (very tasty, with high energy value) and their convenience which are new.  Finally, snacking can reflect uneasiness and become more source of guilt as the "health concern" associated with the diet increases and generates standards (which are often variable...)

How  many  times do we eat during the day?

In our society, the three-meals-per-day model is considered the rule.  But how can we define eating patterns or a meal?  Is a cup of coffee and a cookie, eaten in the office, part of the breakfast eaten an hour earlier?  Or do they constitute a separate instance of food intake?  Above all, are they perceived as such by the eater?  Currently, there is no single definition accepted by all.
Supplementary question: how can we know  the exact number of food intakes in a given period (day, week, etc.)?

These two questions, which are related, raise complicated methodological problems.  Whether it involves the number of food intakes, their periodicity or their content, direct observation is difficult.  Also, generally, food intake questionnaires or diaries are used (for 24 or 48 hours, for seven days, etc.) or again, meetings with health professionals using standardized methodologies of questioning. Despite the efforts of standardization, high margins of error persist.  However, it would be scientifically incorrect to apply systematic empirical corrections to the subject's declarations.

Despite the difficulties in methodology and interpretation, direct observation of food intake followed by in-depth food consumption interviews have been conducted by J. P. Poulain (1997) on adults in the setting of communal meals eaten in company cafeteria.  The majority of subjects stated that they eat three meals per day, while forgetting, for example, the fruit from the midday meal saved and eaten later, or indeed coffee breaks with cookies, cakes or sweets eaten any time of the day.  It appears that approximately 19% of the population actually eat only three meals per day; about 41% eat four or five times per day and about 40% eat six or more times per day (up to 15 times daily).  In these interviews, it is interesting to observe that some of these same people, in good faith, do not consider that such food intake between meals alters their model of three meals per day.  Eating between meals, snacking, is not perceived as food intake.

How  many meals should one eat per day?

In J.P. Poulain's study, 52% of the people interviewed considered eating between meals "truly bad," and 81% thought that snacking can be a "source of problems" for the health.
In 1997, an interdisciplinary workshop showed that the three-meals-per-day cultural model does not correspond to any biological, chronobiological or physiological determinism.

Furthermore, there is nothing to indicate that there might be a "wisdom of the body" which would make it possible to define when and how much to eat.  The frequency, structure of meals, their periodicity and timing are determined much more by cultural conventions which can vary in time and space: thus Spanish habits are very different from those of English-speaking countries or of Scandinavia.

Moral or social considerations determine much more the attitude toward snacking than a verified scientific reality.  Furthermore, exceptions and tolerances exist: thus it is generally considered that young children as well as elderly adults should eat more frequently during the day.  Such beliefs are not based on any scientific data.

In developed countries, the multiplication of food intake outside of meals is perceived as a desocialization of individuals, a break in social and identity-related settings, symbolized by meals eaten with others.  Consequently, snacking is perceived as a selfish and individualistic action, which transgresses the social fabric and its conventions.

Finally, no currently available data, apart from cultural and social rules, make it possible to pinpoint a specific number of instances of food intake per day.

Multiple food intake and health

The repeated consumption of some foods, outside of meals, unquestionably has a harmful effect on oral hygiene and cariogenesis.  The intake of any food lowers the pH in the mouth, which, when below 5.5, promotes the harmful effects of the bacterial flora and bacterial plaque on dental enamel.  The fragilizing effect on enamel and the decrease in the mouth's pH vary according to the type of foods eaten: the most caries-inducing foods are so-called "sticky foods," sweet and/or fatty.

Many allegations involve multiple instances of food intake and their consequences on health: some authors believe that a high number of food intakes may lead to obesity.  Others propose the idea that an increase in the number of times food is consumed would lead to a better control of weight by increasing energy expenditure and decreasing the formation of fatty mass.  Currently, no scientific consensus exists on this point, all the more because comparisons must be made with equal calorie intake.
 
Lastly, multiple food intake, and in particular snacking are also held responsible for an appreciable increase in energy intake.  This criticism is partly justified when snacking involves the consumption of sweet beverages, whose "liquid" calories are poorly taken into account by the body and in the mechanisms of satiety; this is also the case when snacking involves the intake of high-calorie foods that the consumer does not incorporate into the implicit balance of a diet (insert 3).

Conclusion

Eating outside of meals seems to be better experienced when society does not moralize about this topic.  The "ideal" number of meals for the human body is not known.  There is only one certainty: everything that we eat is incorporated, consciously or unconsciously, into the daily energy balance.
Thus the inherent risk of snacking is above all related to not perceiving it as a dietary intake.

Prof. Matty Chiva
University Paris X - Nanterre

Bibliography
- Chiva M. Le mangeur et le mangé : la subtile relation d'une complexité fondamentale, in Giachetti I. (ed.), Identités des mangeurs, images des aliments ;1996 ; Polytechnica, Paris, pp 11-30
- Periodicity of Eating and Human Health, British Journal of Nutrition ;1997 ; 77, supplement n°1
- Poulain J.P. ; Sociologies de l'alimentation ; 2002, PUF, Paris