A large-scale study called "Diogenes"
has investigated the optimum dietary composition for
preventing and treating obesity.
The results were recently published in the New England
Journal of Medicine by researchers at the Faculty of Life
Sciences (LIFE), University of Copenhagen.
If you want to lose weight, you should maintain a diet that
is high in proteins with more lean meat, low-fat dairy products
and beans and fewer refined starch calories such as white
bread and white rice. With this type of diet, most people can
also eat until they are full without counting calories and
without gaining weight. Interestingly, this study also concludes
that the official dietary recommendations are not sufficient for
preventing obesity.
The objective of the Diogenes Study has been to compare
the official dietary recommendations in Europe, including the
Danish recommendations, with a diet based on the latest
knowledge specifically about the importance of proteins and
carbohydrates for appetite regulation.
A total of 772 European families participated, comprising
938 adult family members and 827 children. The overweight
adults initially followed an 800 kcal/day diet for eight weeks,
losing an average of 11 kg (approx. 24 lbs.) They were then
randomly assigned to one of five different low-fat diet types
which they followed for six months in order to test which diet
was most effective at preventing weight regain. Throughout
the project, the families received expert guidance from
dietitians and were asked to provide blood and urine
samples.
The design of the study comprised the following
five diet types:
1) A low-protein diet (13% of energy consumed) with a high
glycemic index (GI)*
2) A low-protein, low-GI diet
3) A high-protein (25% of energy consumed), low-GI diet
4) A high-protein, high-GI diet
5) A control group which followed the current dietary
recommendations without special instructions regarding
glycemic index levels
A high-protein, low-GI diet works best...
A total of 938 overweight adults with a mean body mass
index (BMI) of 34 kg/sq m were initially placed on an
800-kcal-per-day diet for eight weeks before the actual diet
intervention was initiated. A total of 773 adult participants
completed this initial weight-loss phase and were then
randomly assigned to one of five different diet types, where
548 participants completed the six-month diet intervention
(completion rate of 71%).
Fewer participants in the high-protein, low-GI groups
dropped out of the project than in the low-protein, high-GI
group (26.4% and 25.6%, respectively, vs. 37.4%; P = 0.02
and P = 0.01 for the two comparisons, respectively). The
initial weight loss on the 800-kcal diet was an average of
11.0 kg (approx. 24 lbs.)
The average weight regain among all participants was 0.5 kg
(approx. 1.1 lbs), but among the participants who completed
the study, those in the low-protein/high-GI group showed the
poorest results with a significant weight gain of 1.67 kg
(approx. 3.5 lbs)The weight regain was 0.93 kg (approx. 2 lbs)
less for participants on a high-protein diet than for those on a low-protein diet and 0.95 kg less in the groups on a low-GI
diet compared to those on a high-GI diet.
The children's study...
The results of the children's study have been published in
a separate article in the American medical journal Pediatrics.
In the families, there were 827 children who only participated
in the diet intervention. Thus, they were never required to go
on a diet or count calories, they simply followed the same diet
as their parents. Approx. 45% of the children in these families
were overweight. The results of the children's study were
remarkable: In the group of children who maintained a high-
protein, low-GI diet the prevalence of overweight dropped spontaneously from approx. 46% to 39% -- a decrease of
approx. 15%.
Proteins and low-GI foods...
The Diogenes Study shows that the current dietary
recommendations are not optimal for preventing weight
gain among overweight people. A diet consisting of a slightly
higher protein content and low-GI foods ad libitum appears
to be easier to observe and has been documented to ensure
that overweight people who have lost weight maintain their
weight loss. Furthermore, the diet results in a spontaneous
drop in the prevalence of overweight among their children.
About Glycemic Index...
The glycemic index is a measure of the ability of
carbohydrates to increase blood glucose levels when
absorbed in the body. Food with a low-glycemic index (LGI)
causes blood glucose levels to increase more slowly and to
lower levels compared to high-carbohydrate foods with a
high glycemic index.
Drastic increases in blood glucose levels give rise to several
potentially undesirable effects that can influence the body's
metabolism as well as our ability to perform mentally. It is
therefore most appropriate to maintain a diet that results in
slow digestion and thus more stable blood glucose levels and
greater satisfaction.
A diet with a high protein content contains many protein-rich
foods such as lean meat, poultry, fish, eggs and low-fat dairy
products. Legumes also contain high levels of protein, as do
nuts and almonds. Proteins are significantly more filling than
both carbohydrates and fat.
Recommendations and Special Requirements
for a Low-Glycemic Diet...
The glycemic index applies to carbohydrate-containing foods.
The recommendations are that some types of fruit may be
consumed such as apples, pears, oranges, raspberries and
strawberries. Other types should be eaten in only very limited
amounts, including bananas (especially overripe bananas),
grapes, kiwi, pineapple and melon. Nearly all vegetables are
permitted, with the exception of corn, which should be limited.
Carrots, beets and parsnip should preferably be eaten raw.
With regard to cereal-based foods (bread, grain, corn, hulled
grains and breakfast products), the goal is to eat as many
coarse and wholegrain foods as possible, such as wholegrain
breads with many kernels, wholegrain pasta, whole oats and
the special varieties of wholegrain cornflakes.
Potatoes should be cooked as little as possible. Try to stick
to new potatoes, and it is a good idea to eat them cold. Avoid
mashed potatoes and baked potatoes.
Pasta should be cooked "al dente" and is best eaten cold.
Choose rice varieties such as brown rice, parboiled rice
or basmati.
White bread without kernels, white rice and sugary breakfast
products should be avoided. In general, sugar intake should
be limited, not so much because of its GI but to avoid all
those 'empty calories'.
Recommended GI values:
Over 70 -- high GI 55-70 -- medium GI Under 55 -- low GI
High-GI foods can still be healthy and vice versa. Carrots,
for instance, have a high GI (72), while chocolate has a low
GI (49). Fats help decrease the absorption of sugar in the
blood, which means that carbohydrate-containing foods and
fat can have a low GI.
Example of a day's menu for a high-protein, low-GI diet:
If you want to maintain a high-protein, low-GI diet, here's a
sampling of daily meals, comprised as follows:
Breakfast: Low-fat yogurt with muesli (without added sugar),
wholegrain crispbread with low-fat cheese, and an orange.
Mid-Morning: Vegetable sticks and low-fat cheese sticks
or low-fat cottage cheese.
Lunch: Wholegrain rye bread with lean meat, turkey or
chicken cold cuts, mackerel, herring or sardines in tomato
sauce and misc. vegetables.
Afternoon: Wholegrain rye bread with low-fat liver paté and
cucumber.
Dinner: Stir-fried turkey with vegetables and wholegrain pasta;
avocado salad with feta cheese and peas. It is best to drink
water or low-fat milk with meals.
To summarize...
There is nothing particular about this diet with the exception
of the above-mentioned limitations, special cooking instructions
and the fact that certain vegetables should be eaten raw. This
diet generally complies with the official dietary recommendations
of eating plenty of fruit and vegetables, low-fat foods, plenty of
fiber and limiting total sugar intake.
The study was conducted by eight European research centers including The Faculty of Life Sciences (LIFE)
Editor's Note: This article is not intended to provide medical advice, diagnosis or treatment.
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