Green tea catechin plus caffeine supplementation to a high-protein diet
has no additional effect on body weight maintenance after
Rick Hursel and Margriet S Westerterp-Plantenga
Background: Green tea (epigallocatechin gallate 1 caffeine) and
protein each were shown to improve body weight maintenance after
Objective: We investigated the effect of a green tea–caffeine mix-
ture added to a high-protein (HP) diet on weight maintenance (WM)
after body weight loss in moderately obese subjects.
Design: A randomized, placebo-controlled, double-blind parallel
trial was conducted in 80 overweight and moderately obese sub-
jects [age (mean 6 SD): 44 6 2 y; body mass index (BMI; in kg/
m2): 29.6 6 2.0] matched for sex, age, BMI, height, body mass,
and with a habitually low caffeine intake. A very-low-energy diet
intervention during 4 wk was followed by 3 mo of WM; during the
WM period, the subjects received a green tea–caffeine mixture
(270 mg epigallocatechin gallate 1 150 mg caffeine/d) or placebo,
both in addition to an adequate protein (AP) diet (50–60 g protein/
d) or an HP diet (100–120 g protein/d).
Results: Subjects lost 7.0 6 1.6 kg, or 8.2 6 2.0%, body weight
(P , 0.001). During the WM phase, WM, resting energy expendi-
ture, and fat-free mass (FFM) increased relatively in both the HP
groups and in the AP 1 green tea–caffeine mixture group (P ,
0.05), whereas respiratory quotient and body fat mass decreased, all
compared with the AP 1 placebo group. Satiety increased only in
both HP groups (P , 0.05). The green tea–caffeine mixture was
only effective with the AP diet.
Conclusion: The green tea–caffeine mixture, as well as the HP diet,
improved WM independently through thermogenesis, fat oxidation,
sparing FFM, and, for the HP diet, satiety; a possible synergistic
effect failed to appear. Am J Clin Nutr 2009;89:822–30.
The increasing incidence of obesity is a recognized medical
problem in developed countries (1). Obesity is an important
factor for a number of diseases, including coronary heart dis-
eases, hypertension, type 2 diabetes, pulmonary dysfunction,
osteoarthritis, and certain types of cancer (2–4). The main cause
for the development of obesity is increased energy intake during
sustained or decreased energy expenditure. Weight loss and loss
of body fat can thus be achieved by reducing energy intake and
at the same time sustaining energy expenditure. Treatment of
obesity is beneficial in that weight loss reduces the risk of
mortality and morbidity. Even modest weight loss, 5–10% of the
initial body weight, already leads to beneficial health effects (5–
7). Modest weight loss is a realistic goal for most subjects (5, 7).
However, long-term maintenance of the body weight lost can be
described as unsuccessful. Most studies on weight maintenance
show an undesired weight regain (8–12), indicating that subjects
did not change their eating and activity behaviors adequately
(13). Interventions to improve long-term weight maintenance
are needed to treat obesity effectively. A rapidly growing ther-
apeutic area is the use of natural herbal supplements. One of
these agents is a green tea–caffeine mixture [epigallocatechin
gallate (EGCG) plus caffeine], whose claimed antiobesity pro-
perties have been ascribed to increase thermogenesis and fat
oxidation (14–20). A green tea–caffeine mixture contains caf-
feine that may stimulate thermogenesis and fat oxidation
through inhibition of phosphodiesterase, an enzyme that de-
grades intracellular cyclic AMP, and through antagonism of
the negative modulatory effect of adenosine on increased nor-
adrenaline release (14). Human studies have shown that caffeine
stimulates thermogenesis and fat oxidation (15–17, 21, 22). In
addition, green tea–caffeine mixtures contain large amounts of
tea catechins that were shown to inhibit catechol O-methyl-
transferase, an enzyme that degrades norepinephrine (18). Also
in humans, a green tea–caffeine mixture was shown to stimulate
thermogenesis and fat oxidation in the short term (19, 23, 24).
Dulloo et al (19) showed that the effect of a green tea extract
containing 90 mg EGCG 1 50 mg caffeine was greater than that
attributed to 50 mg caffeine alone. On the basis of these studies
in humans, we hypothesized that a green tea–caffeine mixture
would reduce body weight regain in humans after weight loss,
possibly through a thermogenic effect (19, 23–25). Moreover,
we have shown before that a relatively high-protein (HP) diet
improves body weight maintenance after body weight loss (26,
27) (R Hursel and M Westerterp-Plantenga, unpublished ob-
servations, 2008). Thus, the question remains whether there may
1From the Maastricht University, Maastricht, Netherlands.
2Supported by NUTRIM, Maastricht University, Maastricht, Netherlands.
3Reprints not available. Address correspondence to R Hursel, Department
of Human Biology, Maastricht University, PO Box 616, NL-6200 MD Maas-
tricht, Netherlands. E-mail: email@example.com.
Received September 30, 2008. Accepted for publication December 16, 2008.
First published online January 28, 2009; doi: 10.3945/ajcn.2008.27043.
Am J Clin Nutr 2009;89:822–30. Printed in USA. ? 2009 American Society for Nutrition
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be a synergistic effect of a green tea–caffeine supplementation
added to an HP diet. The following study addresses this research
question, with the aim to investigate whether a green tea–
caffeine mixture added to an HP diet may improve weight
maintenance by preventing or limiting weight regain after
weight loss of 5–10% in moderately obese subjects with a low
habitual caffeine intake.
SUBJECTS AND METHODS
differences observed in fat mass (FM) in a previous study (28).
With an observed difference of 2.2 kg and an SD of the pop-
ulation of 4.5 kg, it was calculated that after taking a 10%
dropout into account ?80 subjects were needed to achieve suf-
ficient power (90%) to observe significant (P , 0.05) changes in
body weight and FM as a result of treatment. Male and female
overweight and moderately obese subjects (n ¼ 100), aged be-
tween 18 and 60 y, with a body mass index (BMI; in kg/m2)
between 25 and 35, were recruited from the local population in
2006. They underwent a medical screening. Selection was based
on being in good health, being a nonsmoker, not using medi-
cation, ingesting ?100 mg caffeine/d (from coffee, tea, choco-
late, cola, or energy drinks; the main source of caffeine intake
was coffee), not drinking green tea habitually, and being at most
a moderate alcohol user. Ninety-two subjects were eligible for
participation in the study. During the 4-wk weight-loss period,
12 subjects dropped out of the study, 8 because of moving,
changing jobs, or going on vacation and 4 because of not being
able to follow the very-low-energy diet (VLED). The remaining
80 subjects were further divided into 4 stratified groups ac-
cording to, respectively, sex (11 women and 9 men per group),
BMI (27.0 6 2.6), age (44 6 2 y), and weight loss (7.0 6 1.6
kg). All subjects gave their written informed consent. The
Medical Ethics Committee of the Academic Hospital in Maas-
tricht approved of the study. Subsequently, subjects were ran-
domly assigned to 4 groups: a green tea–caffeine mixture
treatment 1 adequate protein (AP) group, a green tea–caffeine
mixture treatment 1 relatively HP group, an AP 1 placebo
group, and an HP 1 placebo group for the weight-maintenance
phase (Figure 1).
During this weight-maintenance phase, the subjects received
a green tea–caffeine mixture [45 mg EGCG 1 25 mg caffeine 1
380 mg placebo (vegetable oil)/capsule; 6 capsules/d; 2 capsules
before each meal (corresponding to 2–3 cups of green tea/d and
caffeine content alone is comparable to 1–2 cups of coffee/d)] or
placebo (450 mg vegetable oil/capsule; 6 capsules/d; 2 capsules
before each meal). The dosage of EGCG was the same as used
by Dulloo et al (19); the dosage of caffeine was lower (29).
The capsules were manufactured by Novartis CH, Nyon,
The capsules with a green tea–caffeine mixture or placebo
were given in addition to an AP diet or an HP diet. With both
diets, subjects received a prescription with examples of menus
that represented a just-adequate energy intake, based on subjects’
resting energy expenditure (REE) multiplied by their physical
activity factor (for measurement description, see Baseline mea-
surements) or, if the subjects’ physical activity factor was not
measured, the group average of 1.6 was applied.
In the AP group, the prescribed energy intake consisted of 50–
60 g protein (’10% of energy from protein); in the HP group, the
prescribed energy intake consisted of 100–110 g of protein
(’20%of energy fromprotein). The additionalprotein wasgiven
as 50 g calcium caseinate, a powder soluble in any fluid, provided
by Novartis CH. The subjects were instructed by the dietitians
how and when to prepare and consume the diets. Moreover, the
subjects had to collect 24-h urine specimens before the weight-
maintenance diet started and during the 6th and 12th week of the
Anthropometry. Body weight was measured with a digital
balance (model 707; Seca, Hamburg, Germany; weighing ac-
curacyof0.1 kg) with subjects in underwear,in afasted state, and
a wall-mounted stadiometer (model 220; Seca). BMI was cal-
culated. The distribution offat was investigated by measuring the
waist circumference at the site of the smallest circumference
between the rib cage and the ileac crest, with the subjects in
Body composition. Total body water (TBW) was measured with
the use of the deuterium (2H2O) dilution technique (30, 31). In
the evening, the subjects ingested a dose of deuterium-enriched
water after collecting a background urine sample. After con-
sumption of the deuterium-enriched water, no fluid or food was
consumed. The following morning a urine sample from the
FIGURE 1. Flow diagram of the progress through the phases of the study. VLED, very-low-energy diet; GT, green tea–caffeine mixture; PL, placebo.
PROTEIN AND GREEN TEA EFFECTS ON BODY WEIGHT
by guest on November 17, 2015
Fraser GE. Vegetarian diets: what do we know of their effects on common chronic diseases? Am J Clin Nutr 2009;89(suppl):
In the Introduction it was stated that the Health Food Shoppers’ Study and the Oxford Vegetarian Study observed deaths only.
This was so for most causes; however, data on incident (fatal and nonfatal) cancers were also available.
Mendez MA, Covas MI, Marrugat J, Vila J, Schro ¨der H. Glycemic load, glycemic index, and body mass index in Spanish adults.
Am J Clin Nutr 2009;89:316–22.
In Table 2 on page 319, the mean (95% CI) value for the third tertile of dietary glycemic load in men is erroneous. Instead of
‘‘120 (118, 121),’’ the value should be ‘‘179 (177, 180).’’
Koletzko B, von Kries R, Monasterolo RC, et al. Can infant feeding choices modulate later obesity risk? Am J Clin Nutr
The last name of the third author should be ‘‘Closa’’ instead of ‘‘Monasterolo.’’ The author’s name should be listed as
‘‘Ricardo Closa.’’ The last name of the fourth author should be ‘‘Escribano’’ instead of ‘‘Subı ´as.’’ The author’s name should
be listed as ‘‘Joaquı ´n Escribano.’’
Hursel R, Westerterp-Plantenga MS. Green tea catechin plus caffeine supplementation to a high-protein diet has no additional
effect on body weight maintenance after weight loss. Am J Clin Nutr 2009;89:822–30.
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