of Western populations and the majority of Asian
and native populations (e.g. Australian aborigi-
nals) due to a deficiency of the enzyme lactase,
whereas fructose is best absorbed in the presence
of other carbohydrates in the intestine, and is
poorly absorbed when consumed in large
amounts on its own (for review, see Gudmand-
Hoyer 1994; Southgate 1995). The incomplete
digestion of starch is now also recognized. The
termresistant starchhas been coined to describe
starch fractions in food that pass undigested into
the large bowel. These include particles that
are indigestible due to lack of physical contact
with digestive enzymes (such as only partially
chewed or milled grains and legumes, or whole
seeds), or starch found in ungelatinized granules
such as in raw bananas, uncooked potatoes, or
76 nutrition and exercise
high amylose-content cereals. Finally, some
starch is made resistant by cooking or process-
ing. Foods that have been baked at high tempera-
tures (e.g. bread, cornflakes), or cooled after
being cooked to make the starch soluble or gela-
tinized (e.g. cold baked potato) may contain sig-
nificant amounts of starch that has retrograded
(had the water-bound structure disturbed). For
review, see Englyst et al. (1992). There is an argu-
ment to include resistant starch as a component
of dietary fibre.
In any case, the view of dietary fibre needs to
be updated to recognize it as a group of diverse
compounds which are far from inert. Although
they may be undigested in the small intestine,
many are fermented by bacteria in the large
bowel and may provide a number of their healthTable 5.2Examples of the overlap between the nutritional and structural classification of CHO-rich foods.
‘Nutritious’* ‘Less nutritious’‘Simple’ CHO-rich foods Fruit Sugar (sucrose)
Fruit juice Honey, jam, syrups
Canned fruit Soft drinks, flavoured mineral
Dried fruit water
Flavoured milk, yoghurt and other Sports drinks
sweetened dairy foods (especially ‘Carbohydrate loading’
low-fat types) supplements
Liquid meal supplements Sweets, chocolates
Some sports bars Jelly, mousses and high-fat
desserts
Ice cream
‘Complex’ CHO-rich foods Bread, muffins, bagels Pastry
Breakfast cereals Potato crisps
Pasta and noodles Chips/fries
Rice and other grains Croissants
Starchy vegetables (e.g. potatoes, corn)
Legumes and pulses
Pizza bases
CHO-rich foods with mixture Low-fat cake and dessert recipes High-fat cakes, pastries, biscuits,
of ‘simple’ and ‘complex’ Sweetened and fruit-containing desserts
CHOs breakfast cereal Granola/muesli bars
Baked beans Some sports bars
Some fruits and vegetables (e.g.
bananas, pumpkin)
Some sports bars
- In this chapter, ‘nutritious’ foods are defined as those providing significant amounts of protein and macronutri-
ents, and contributing less than 30% of energy from fat. ‘Less nutritious’ foods are those providing insignificant
amounts of other nutrients, and/or having a fat content of more than 30% of total energy.