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SA JOURNAL OF DIABETES & VASCULAR DISEASE
REVIEW
VOLUME 12 NUMBER 2 • NOVEMBER 2015
51
Understanding dieting
BM Naidoo, A Martens, GB Adams, R lachman, LA Everson, AJ Jackson, V Tivers,
LB Addicott, E Walters
Compiled by Grey’s Hospital dietitians:
Miss BM Naidoo,
chief dietitian, Critical Care and Surgery
e-mail:
Dietitians.Greys@kznhealth.gov.zaMiss A Martens
, dietitian, Medicine and Surgery
Mrs GB Adams
, chief dietitian, Neonatal Critical Care, General Medicine/
Paediatrics/Surgery
Mrs R Lachman
, assistant director, HOD Dietetics
Miss LA Everson
, senior dietitian, Paediatric Surgery and Oncology
Miss AJ Jackson
, dietitian, Cardiac Care, Surgery and Maternity
Miss V Tivers
, dietitian, Paediatric Critical Care, Department of Surgery
and Orthopaedics, Grey’s Hospital, Pietermaritzburg
Miss LB Addicott
, dietitian, Medicine, Paediatric Medicine and
Oncology, and Maternity
Mrs E Walters
, dietitian, Medical Paediatrics, Medicine and Orthopaedics
S Afr J Diabetes Vasc Dis
2015;
12
: 51–52
Background
Globally there is a marked increase in the incidence of obesity.
1
As
a society, these increasing rates can be attributed to an increased
calorie intake, changes in dietary composition, decreasing levels of
physical activity, and the active promotion of food consumption by
industry.
1
On a more personal level, factors that contribute to weight gain
for the individual include poor dietary intake and food choices,
skipping meals, excessive intake of sugar-containing food and
drinks, a lack of exercise and inactivity; psychological factors such
as depression, anxiety and stress; biomedical factors such as genetic
make-up, disorders of metabolism and medical conditions; use of
medication; inflammatory processes; and any factors that may
result in reduced mobility.
2
Overweight and obesity are associated with a higher risk of
several related conditions, termed chronic diseases of lifestyle, such
as chronic kidney disease,
1
cardiovascular disease, diabetes and
hypertension. Data show that most deaths that can be attributed
to overweight and obesity are due to a cardiovascular event.
Even with aggressive drug therapy to target high blood pressure
and cholesterol, increased rates of overweight and obesity are
expected to have significant negative health effects and increase
the prevalence of diabetes, osteoarthritis, certain types of cancer,
major vascular diseases,
1
and sleep apnoea.
3
All of these conditions
have the potential to lower the quality of life of an individual.
Weight loss of only five to 10% in obese individuals significantly
reduces the above risks.
4
Sustained weight loss of as little as three to
5% is likely to result in clinically significant reductions in triglyceride
and blood glucose levels, and the risk of developing type 2 diabetes,
and better long-term control of blood glucose levels.
5
Goals
Our goal as a society is to reduce the prevalence of obesity and
associated risks. For the individual living with excess weight every
day, a self-imposed goal tends to be more personal and urgent,
with the intention of simply losing as much weight as necessary to
be comfortable and confident, as quickly as possible.
There are diets that promise rapid weight loss, with minimal
effort, but is it realistic to expect this when weight gain has been
gradual? And if it is this simple, why does the topic spark such
controversy?
Fad diets
A fad diet is the term used to describe diets that gain popularity
and then quickly diminish in importance. The loss of interest may
be the result of the difficulty maintaining the extreme measures
used to encourage weight loss in some of these diets.
Some common characteristics of fad diets are the rigid menus
and monotonous food choices, unlimited foods of some type, a
lack of scientific evidence to support the claims, the introduction
of ‘magical’ foods, food combinations or newly discovered secrets,
and the use of scientific jargon and incomplete information or half-
truths. These diets may also involve the purchase of a commercial
product,
6
intermittent fasting,
7
cutting out or excessively restricting
certain food groups, and excessively promoting the value of
another. Some examples are low-carbohydrate diets, which are
high in fat and high or low in protein; the blood group diet; the
alkaline diet; and one-food diets, such as the cabbage soup and
grapefruit diets.
Fad diets sometimes do not acknowledge the importance of
physical activity as part of a weight-loss plan,
6
disregarding one of
the most important components of a healthy lifestyle. Appropriate
weight loss requires a combination of diet, exercise and behavioural
modification.
8
Fad diets can also present the dieter with little variety, which
makes it difficult to sustain, and necessitates a lot of planning. The
lack of balance of nutrients can mean supplementation is necessary,
which can be expensive to maintain.
9
Some fad diets are sometimes simply a low-kilojoule diet by
a different name, and therefore can result in weight loss.
6
Low-
carbohydrate diets can result in initial rapid weight loss, as they are
also low-kilojoule diets. However, energy–protein balance studies
have shown that the greater weight loss on a low-carbohydrate,
high-fat diet is accounted for by losses in water.
10
The aim of
weight loss diets should be the loss of weight from fat. Water and
muscle loss, among the other consequences of fad diets, can be
detrimental to one’s health.
Significant consequences of fad diets
Rapid weight loss, greater than 500 g to 1 kg per week, represents
loss from lean muscle mass and fluid.
2
Weight regained thereafter
is usually fat rather than muscle, and this yo-yo dieting effect has
adverse effects on the heart and can even lead to cardiac injury
and death.
2
High-protein diets can place great strain on the kidneys, due to
the greater production of waste products of protein breakdown,