Newsgroup: it.salute.alimentazione
Titolo: In difesa delle diete proteiche

Title: ECO: High Protein Diets More Effective At Maintaining Weight Loss
       "ECO: High Protein Diets More Effective At Maintaining Weight Loss"
      By Mark Pownall HELSINKI, FINLAND -- June 4, 2003 -- Higher protein
diets are more effective at maintaining weight loss in overweight people who
previously lost weight on very low-energy diets, suggest researchers. Dr
Manuela Lejeune, of the University of Maastricht in the Netherlands,
presented study findings at the European Congress of Obesity, being held
here. One hundred and twenty subjects who lost an average of 6 kg in 4 weeks
while following a very low-energy diet were then randomised to follow either
a moderately restricted diet (control group), or a diet similar in calories
but higher in protein content (study group). The initial weight loss on the
very low-calorie diet was equivalent to a mean loss of 7.5% of initial body
weight. The high protein group followed a similar diet but also received a
drink containing 48.2g/day protein, resulting in an additional 30g of
protein per day, when checked by objective nitrogen balance techniques. The
high-protein drink was a partial replacement for lunch. Those on the high
protein diet regained a mean 0.8 kg in the 6 months after the initial weight
loss, compared to 3.0 kg regained on the control diet. The difference was
statistically significant. Body mass regain in patients on the high protein
diet was of fat-free mass, Dr. Lejeune said. The control diet provided 15%
of its energy as protein, while 18% of the higher protein diet by energy was
protein. The subjects, well matched at baseline, also showed a difference in
waist circumference at the end of the 6-month study period. Those on the
high-protein diet lost an average 1.2 cm around the waist, compared to a
gain of 0.5 cm for those on the control diet. Similarly, those on the
high-protein diet reported high feelings of satiety than did the control
group, and they had a higher respiratory quotient. There were no
statistically significant differences between the 2 groups in blood test
results, physical activity or fat free mass. Dr Lejeune concluded: "Despite
no differences in attitudes to eating, a protein intake of 18% as energy
versus 15% as energy resulted in improved weight maintenance, as well as
improved fat distribution based on body waist circumference, and improved
substrate oxidation and satiety." She explained: "In the short term, weight
loss is often successful, but weight maintenance in the long term is more
difficult. Additional protein intake may contribute to the storage of fat
free mass, may increase satiety and have a lower energy storage efficiency
during overfeeding. The result may be that higher protein diets have a
higher cost of weight gain." In answer to questions from the floor of the
congress, Dr Lejeune said that the patients in the control group had not
received a lunchtime drink and acknowledged that this left open the
possibility that some of the difference between the two groups could be
accounted for by the placebo effect. [Study title: Additional protein intake
limits weight gain after weight loss in humans. Abstract t4:02]
Ciao
Gello

 by energy was protein.
Piuttosto interessante, ma avrei qualche cautela a definire
"dieta proteica" una dieta al 18% di calorie dalle proteine.
Poi, quando si gioca con le percentuali, bisogna sempre vedere se
certi effetti dipendono dall'aumento di una parte o dalla diminuzione
di altre due parti. A parità di calorie, una dieta con più proteine
automaticamente ha meno grassi e meno carboidrati, ed è difficile
capire se il risultato dipende dalle proteine aumentate o magari dai
carbo e dai grassi che sono diminuiti. O da tutti e due/tre.
Forse sarebbe molto più chiaro parlare direttamente di grammi per
ogni macronutriente, eventualmente in rapporto al peso del soggetto,
piuttosto che fare alchimie con il totale e le percentuali.
Quello che invece è abbasatanza evidente, e questo studio non è che
l'ennesima riprova, è che due regimi alimentari con la stessa identica
quantita di calorie possono avere effetti sensibilmente diversi sia sul
peso corporeo, sia soprattutto sul rapporto tra massa grassa e massa
magra, laddove sia diversa (anche leggermente, come in questo caso)
la proporzione reciproca tra i vari macronutrienti.
Quindi non è affatto vero che le variazioni di peso dipendano tutte
e sole dal conteggio delle calorie. Ammesso che ci sia ancora in
giro qualcuno che lo creda.
Xlater
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Direi che hai colto nel segno ;-)
Ciao
Gello