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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 25, No 6, November/December 2014
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AFRICA
the treatment of corpulence.’ The key points in the Banting diet
were his method of reducing obesity by avoiding fat, starch and
sugar in the food. Therefore the proposal that the Banting diet is
similar to the Noakes high-fat diet
3
appears to need re-appraisal.
Banting also made wider overall claims that the diet was ‘a
simple remedy to reduce and destroy superfluous fat; it may
alleviate if not cure gout; prevent or eradicate carbuncles, boils,
dyspepsia, makes life more enjoyable, and promotes longevity’.
One interesting small but important point is that Banting took
the fat off the gravy. For these reasons, it seems preferable to
separate the Banting diet from the Noakes low-carbohydrate,
high-fat diet.
Israeli study and new Atkins diet
The low-carbohydrate, high-fat diets that were introduced by
Atkins and his successors
26
have had very wide influence. Some
of the key features are as follows, with the relevant book pages
given in brackets:
•
Protein intake though high has recommended protein ranges
(51).
•
Fat intake though also high, has a desirable range (70).
•
Vegetables including avocadoes are the basis of the permitted
carbohydrate intake (102).
In a major landmark Israeli diet, the new Atkins diet was
compared with others from the same Israeli population group
in a dedicated communal restaurant where the food intake
could be monitored.
27
In the group given the new Atkins diet,
besides weight loss, the blood cholesterol pattern showed some
favourable changes.
In the comparative group taking a calorie-limited
Mediterranean diet, similar changes were found in weight loss
and blood lipid levels. However, the Mediterranean diet was
calorie limited whereas the Atkins group had a spontaneous loss
of appetite. The molecular mechanism to explain the appetite
loss is not clear. Reservations are that there was no placebo
group and the study was too short to judge any clinical effects
on cardiovascular events.
A broadly similar conclusion was reached in a meta-analysis
of diets of varying carbohydrate and lipid composition. The new
Atkins diet is one of several reduced-calorie diets that have all
resulted in clinically meaningful weight loss, regardless of which
macronutrients they emphasised.
28
What about high-fat weight-losing diets?
The two potential problems with high-fat diets
lie in their adverse
effects on the blood lipoprotein pattern, and on the impairment
of specific mental functions, as observed by Kieran Clarke
in Oxford students. In the Oxford study, a short-term, high-
fat, low-carbohydrate diet led to higher circulating free fatty
acid (FFA) concentrations, impaired patterns of myocardial
high-energy phosphate metabolism, and decreased cognition in
healthy subjects.
29
The site of these deleterious effects on the brain was the
hippocampus. In the heart, sophisticated non-invasive nuclear
imaging techniques measured levels of high-energy phosphate
compounds, which were relatively low in those taking the
high-fat diet. The proposal was that elevated circulating FFA
levels were underlying the cognitive and cardiac abnormalities.
Therefore Clarke and her associates concluded that high-fat,
low-carbohydrate diets are potentially detrimental to the human
heart and brain.
29,30
For these reasons, there are arguments to support the view that
the diet overweight persons could best start with is a new Akins
type of diet for weight loss, coupled with an exercise programme,
and then move onto the Mediterranean-type diet to achieve life-
long health benefits, thereby avoiding the cognitive and cardiac
changes of high-fat diets. Therefore starting a diet to lose weight,
such as the new Atkins or Noakes diet, is complementary with
a later switch to the long-term Mediterranean diet. As these diet
types come in sequence, they are not competitive.
The future
A safe prediction is that there will be more editions of existing
major books (Atkins in the USA, Dukan in Europe, Noakes
in South Africa) besides new diet books. New lipid-lowering
pharmaceutical agents are already being tested in large new
outcomes-based studies on their preliminary promise.
The best self-help policy may well be to start with a dedicated
programme for weight loss however achieved, whether by the new
Atkins or Noakes diet, but associated with sufficient exercise. The
next step would be to move on to the modified Mediterranean
diet (Fig. 2) aimed at living longer and living better.
Looking to the far future, having both fish and meat in the
daily diet of large populations would need substantial resources,
which will be increasingly limited as the human race expands.
Maybe the answer will lie in novel fresh nutritional sources such
as algae-based diets.
References
1.
Opie LH.
Living Longer, Living Better; Exploring the Heart–Mind
Relationship
. Oxford: Oxford University Press, 2011. Online: http://
www.amazon.co.uk/Living-Longer-Better-Heart-Mind-Connection/
Fig. 2.
This dietary pyramid starts at the bottom, with low
carbohydrate intake of about 20 g per day, then as
exercise increases, works up to 40 to 100 g of carbohy-
drates per day while maintaining weight loss, with the
lifelong aim of maintaining the ideal weight. Note that
poultry, fish and beef (free of visible fat) are allowed in
the initiating phase. From Opie,
1
page 67.