- This first of these studies involved the recruit-
ment of 34 volunteers who were underfed for three
months to facilitate a weight loss of 10%. This study
highlighted that resting metabolic rate (RMR)
decreased rapidly at first and then more slowly with
continuing weight loss. The second study, carried out
by Keys and colleagues, again exposed a group of male
volunteers to a reduced calorie intake over a period of
24 weeks to achieve a weight loss of 25%. They con-
firmed a decrease in metabolic rate and estimated that
65% of the decrease in metabolic rate could be attrib-
uted to the loss of the metabolic activity of the tissue.
This study also provided useful information in respect
of the symptoms associated with starvation when indi-
viduals adopt restrictive eating patterns. The study
highlighted that many of the signs and symptoms
that people typically associate with people who suffer
with an eating disorder are very likely to develop
in non-eating disordered individuals if they were to
be exposed to a similar extreme reduction in their
dietary intake. These symptoms include an increased
preoccupation with food, adoption of unusual eating
patterns including concoctions of food, spending a
long time consuming food, social withdrawal and a
lowering of mood and an associated decrease in
libido.
ComplicationsPhysical effects of starvation
Malnutrition occurs when is there is a deficiency
of one or more nutrients. It may be mild or severe.
Severe Malnutrition is rare in developed countries but
sadly remains prevalent in many developing countries.
Weight loss is an obvious sign of a diet too low in
calories or energy. Protein-energy malnutrition occurs
when the diet provides too little energy andprotein.
Malnutrition is assessed in terms of degrees of weight
loss in adults, whilst in children height and weight are
used and compared with growth charts. Weight loss in
adults and failure to thrive in children are the most
obvious signs of insufficient energy intake. In adults,
this is usually noticed by a drop in thebody mass index
(BMI), which is a method used to relate weight to
height and is used as part of the process in determining
an individuals’ nutritional status. In children, insuffi-
cient energy intakes are noticed when children fail to
meet expected growth milestones. In the long-term,
stunted growth may result as a consequence of insuf-
ficient energy requirements and children may not
reached an expected height for weight ratio.
It is important to remember that individuals of a
healthy body weight could still be classified as malnour-
ished if they are lacking in essential nutrients. There-
fore, overall nutritional status of individuals cannot be
assessed solely on body weight. Consequently, nutri-
tional assessment screening tools are useful to help
identify individuals who may be at risk of malnutrition
in hospitals, care homes and primary care settings. In
summary, malnutrition may develop owing to a num-
ber of factors including a decreased dietary intake,
increased nutritional requirements or increased losses
or an inability to absorb or utilize nutrients.
Severe cases of low energy intake result in starva-
tion and life threatening conditions called Kwashiorkor
(characterized by protein deficiency) and Marasmus
(primarily a deficiency of energy-providing foods). Mar-
asmus is a chronic condition of semi-starvation, charac-
terized in later stages by muscle wasting and an absence
of subcutaneous fat and to which children adjust, to
some extent, by reduced growth. In Kwashiorkor, sub-
cutaneous fat is usually preserved; muscle wasting
occurs but is often masked by edema (swelling). Overall
the physical effects of malnutrition are dependent on
what nutrients are missing from the diet, for example,KEY TERMS
BMI—This relates weight to height and is used as
part of the nutritional assessment of individuals. BMI
is the weight (in kg) divided by the height (in meters)
squared. The acceptable healthy range is 20–25.
Calorie—The amount of heat needed to raise 1g of
water by 10C. For nutritional purposes the Calorie
(or kilocalorie) is the amount of heat needed to raise
1,000g of water by 10. The modern unit is the joule.
One calorie is a little over 4 joules.
Malnutrition—A disorder resulting from an inad-
equate diet or failure to absorb or assimilate nutrients.
Minerals—Elements that are essential for the body
to function correctly including calcium, iron, phos-
phorous, magnesium, sodium, chloride, iodine,
manganese, copper, and zinc.
Starvation—A long-term consequence of food
deprivation.
Vitamins—Compounds required by the body in
small amounts to assist in energy production and
in cell growth and maintenance. They are essential
for life and with the exception of vitamin D, cannot
be made in the body. They should ideally be con-
sumed from food. However, individuals who strug-
gle to eat can obtain their vitamin requirements
from dietary supplements.Calorie restriction