Michael C Price wrote:
Thanks for the abstract, Olafur.
Here's another. It says
"High-protein foods promote postprandial thermogenesis
and greater satiety as compared to high-carbohydrate,
low-fat foods;"
but of course that leaves the question open as
to the exact causal link between protein and satiey.
Interesting about vitamin C. Perhaps I will have to
exercise!
J Am Coll Nutr. 2005 Jun;24(3):158-65. Related Articles, Links
Strategies for healthy weight loss: from vitamin C to the glycemic response.
Johnston CS.
Department of Nutrition, Arizona State University East, 7001 E. Williams
Field Rd., Mesa, AZ 85212. .
Abstract America is experiencing a major obesity epidemic. The ramifications
of this epidemic are immense since obesity is associated with chronic
metabolic abnormalities such as insulin resistance, dyslipidemia, and heart
disease. Reduced physical activity and/or increased energy intakes are
important factors in this epidemic. Additionally, a genetic susceptibility
to obesity is associated with gene polymorphisms affecting biochemical
pathways that regulate fat oxidation, energy expenditure, or energy intake.
However, these pathways are also impacted by specific foods and nutrients.
Vitamin C status is inversely related to body mass. Individuals with
adequate vitamin C status oxidize 30% more fat during a moderate exercise
bout than individuals with low vitamin C status; thus, vitamin C depleted
individuals may be more resistant to fat mass loss. Food choices can impact
post-meal satiety and hunger. High-protein foods promote postprandial
thermogenesis and greater satiety as compared to high-carbohydrate, low-fat
foods; thus, diet regimens high in protein foods may improve diet compliance
and diet effectiveness. Vinegar and peanut ingestion can reduce the glycemic
effect of a meal, a phenomenon that has been related to satiety and reduced
food consumption. Thus, the effectiveness of regular exercise and a prudent
diet for weight loss may be enhanced by attention to specific diet details.
PMID: 15930480
Thanks for the abstract, the vitamin C connection is very interesting.
As you said the exact link between protein and satiety is an open
question. It would be interesting to see a study comparing a high
protein diet to a low protein diet with a similar GI. The abstract
below seems to indicate that the thermogenesis is the key player in the
satiety effects of a hith protein diet not the GI. While protein
lowers the GI of meals fat also does so mainly by delaying gastric
emptying, so I would expect both the diets in the study below to have
had a medium-low GI and therefore the thermogenesis effect probably was
the main causual factor in the satiety effect.
Eur J Clin Nutr. 1999 Jun;53(6):495-502. Related Articles, Links
Satiety related to 24 h diet-induced thermogenesis during high
protein/carbohydrate vs high fat diets measured in a respiration
chamber.
Westerterp-Plantenga MS, Rolland V, Wilson SA, Westerterp KR.
Department of Human Biology, Maastricht University, The
Netherlands.
OBJECTIVE: Assessment of a possible relationship between perception
of satiety and diet-induced thermogenesis, with different macronutrient
compositions, in a controlled situation over 24 h. DESIGN: Two diets
with different macronutrient compositions were offered to all subjects
in randomized order. SETTING: The study was executed in the respiration
chambers at the department of Human Biology, Maastricht University.
SUBJECTS: Subjects were eight females, ages 23-33 y, BMI 23+/-3 kg/m2,
recruited from University staff and students. INTERVENTIONS: Subjects
were fed in energy balance, with protein/carbohydrate/fat: 29/61/10 and
9/30/61 percentage of energy, with fixed meal sizes and meal intervals,
and a fixed activity protocol, during 36 h experiments in a respiration
chamber. The appetite profile was assessed by questionnaires during the
day and during meals. Diet induced thermogenesis was determined as part
of the energy expenditure. RESULTS: Energy balance was almost complete,
with non-significant deviations. Diet-Induced-Thermogenesis (DIT) was
14.6+/-2.9%, on the high protein/carbohydrate diet, and 10.5+/-3.8% on
the high fat diet (P 0.01). With the high protein/high carbohydrate
diet, satiety was higher during meals (P 0.001; P 0.05), as well as
over 24 h (P 0.001), than with the high fat diet. Within one diet, 24
h DIT and satiety were correlated (r = 0.6; P 0.05). The difference
in DIT between the diets correlated with the differences in satiety (r
= 0.8; P 0.01). CONCLUSION: In lean women, satiety and DIT were
synchronously higher with a high protein/high carbohydrate diet than
with a high fat diet. Differences (due to the different macronutrient
compositions) in DIT correlated with differences in satiety over 24 h.
Publication Types:
* Clinical Trial
* Randomized Controlled Trial
PMID: 10403587 [PubMed - indexed for MEDLINE]
I suspect that the protein is also correcting sub-clinical
deficiencies in various amino-acids (essential and
non-essential).
That might definately be the case sometimes but I don't see how
that would effect weight loss.
If appetite is partly driven to correct dietary deficiencies
-- which I think it is widely aknowledged to be the case
(e.g. pregnant women) -- then correcting amino acid
deficiencies (along with vitamins and minerals)
may supress appetite, independently of any associated
low GI factors.
That's a reasonable theory. In support of your theory dietary
deficiencies such as in protein can cause an increase in thermogenesis
possibly by an increased expression of uncoupling proteins. See this
article for details:
http://saturn.bids.ac.uk/cgi-bin/ds_...ry&format=html
As the abstract below states diet induced thermogenesis might have
evolved as a mechanism to enable animals to eat more in states of
nutrient deficiencies. A deficiency in protein or certain amino acids
might therefore cause an increase in thermogenesis which would probably
be accompanied by an increase in appetite.
Int J Obes Relat Metab Disord. 1999 Nov;23(11):1105-17. Related
Articles, Links
Gluttony and thermogenesis revisited.
Stock MJ.
Department of Physiology, St George's Hospital Medical School,
University of London, London SW17 0RE, UK.
The evolutionary and biological significance of adaptive,
homeostatic forms of heat production (thermogenesis) is reviewed. After
summarizing the role and selective value of thermogenesis in body
temperature regulation (shivering and non-shivering thermogenesis) and
the febrile response to infection (fever), the review concentrates on
diet-induced thermogenesis (DIT). Animal studies indicate that DIT
evolved mainly to deal with nutrient-deficient or unbalanced diets, and
re-analysis of twelve overfeeding studies carried out between 1967 and
1999 suggests the same may be so for humans, particularly when dietary
protein concentration is varied. This implies that the role of DIT in
the regulation of energy balance is secondary to its function in
regulating the metabolic supply of essential nutrients. However,
individual differences in DIT are much more marked when high- or
low-protein diets are overfed, and this could provide a very sensitive
method for discriminating between those who are, in metabolic terms,
resistant and those who are susceptible to obesity.
Publication Types:
* Review
* Review, Tutorial
PMID: 10578199 [PubMed - indexed for MEDLINE]
However if a correction of deficiency in protein or amino acids occured
in any of the previously mentioned studies I would expect thermogenesis
to not have increased much or even decreased on the high protein diet.
Since this was not the case I don't think correction of deficiencies
generally plays a large role in the satiety effect of high protein
diets versus low protein diet unless the low protein diet is *very* low
in protein. A mild deficiency in some amino acids is probably not
enough to cause a significant effect on appetite, you would probably
need a severe deficiency in one or more amino acids for a significant
effect to occur.