Studies supporting Proper Food combining

In this study, as the protein content of the food goes up, its digestibility goes down:

Research Paper
Digestibility index and factors affecting rate of starch digestion in vitro in conventional food preparation A. Urooj *, Sh. Puttraj University of Mysore, Department of Studies in Food Science and Nutrition, Manasagangotri, IND-Mysore-570 006, India. *Correspondence to A. Urooj, University of Mysore, Department of Studies in Food Science and Nutrition, Manasagangotri, IND-Mysore-570 006, India.

ABSTRACT
The rate of starch hydrolysis in ten cereal-based food preparations was studied using an in vitro dialysis system. The foods were incubated with human saliva and porcine pancreatin. The sugars released after 3 h digestion were expressed as digestibility index (DI), the percentage starch digested was determined and correlated with the degree of gelatinization (DG). Granule morphology was also investigated and related with starch availability for hydrolysis. Significant differences were observed in the in vitro starch digestibility of the 10 foods (P > 0.05). The DI ranged from 53 for chapathi to 78 for rice flakes. DI was inversely related to the protein (r = -0.79, P > 0.01), fat (r = -0.63, P > 0.05) and energy (r = -0.61, P > 0.01). Percent starch digested was inversely related to the insoluble (r = -0.49, P > 0.05) and total dietary fiber (r = -0.63, P > 0.01) content of the foods. The SEM results provided a better understanding of granular morphology on cooking and the effect of protein on limiting DG. The results suggest that carbohydrate foods of potential use in the therapeutic diets may be identified by their in vitro digestion characteristics.

Nahrung / Food
See Also:
Molecular Nutrition & Food Research
Volume 43 Issue 1, Pages 42 - 47
In this study (on rats) it is shown that potato starch significantly reduces the utilisation of milk protein in the same meal.

Author(s): Nageswara Rao C ; Narasinga Rao BS

Title: Influence of starches from different sources on protein utilization in rats.

Source: The British journal of nutrition (Br J Nutr) 1978 Jul; 40(1): 1-8

Additional Info: ENGLAND

Standard No: ISSN: 0007-1145 (Print); NLM Unique Journal Identifier: 0372547

Abstract: 1. The role of the starch component of cereals and legumes on the utilization of casein-protein was studied. 2. In comparison with maize starch the legume and potato starches caused a significant lowering of net protein utilization (NPU). And this reduction in NPU could be partially restored by cooking the diets before they were fed to the rats. 3. It is suggested that in NPU studies involving rats the experimental diet should always be cooked so that the conclusions drawn may be applicable to human diets Published Online: 10 Feb 1999

Copyright ? 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This is a quote from the paper by Nageswara Rao C ; Narasinga Rao BS citing a number of other references to published papers where starch adversely effects protein uptake from the same meal.

The amount of dietary protein necessary to meet the protein requirement largely depends on the quality of protein. Among the factors which influence the utilization of dietary protein is thought to be the source of carbohydrate. Net protein utilization (NPU) (Miller &

Bender, 1955) of proteins of plant origin do not always correlate well with the chemical score (Block & Mitchell, 1946). One of the explanations for this may be that some of the non-protein components, such as carbohydrate, of the food may influence protein utilization. Earlier work from this Institute revealed that there are marked differences in in vitro digestibility of starches from different pulses (Srinivasa Rao, 1969). There is also some information in the literature indicating that protein utilization may be affected by the nature of starch (Chang, Soong & Miller, 1967; Marshall, Womack, Hildebrand & Munson, 1969; Buraczewski, Porter, Rolls & Zebrowska, 1971 ; El-Harith, Dickerson & Walker, 1976). Since in developing countries most of the dietary protein is derived from cereals, tubers and pulses, which are also the main source of carbohydrate (starch) in the diet it was considered important to determine the extent to which starch from different dietary sources influences dietary protein utilization

Other studies coming soon but I just wanted to get this up with information I had currently, others I will dig out of references.

Another reference: http://www.drkaslow.com/html/food_combining.html