Carbohydrates and Health

trials report no significant effect on fasting insulin concentration. Nearly all trials
employ energy restricted weight loss diets. The trials vary carbohydrate (from 4%
to 67% energy), fat (from 10% to 54% energy) and protein (from 18% to 37% energy)
between groups. The trial identified in the update search reports no significant
effect of diets differing in the proportion of carbohydrate to fat and protein on
fasting insulin concentration.
Higher carbohydrate, lower fat, average protein diets and fasting blood insulin
concentration
• No effect
• Adequate evidence
Insulin response to oral glucose tolerance test
Higher carbohydrate and lower fat diets compared with lower
carbohydrate higher fat diets
5.102 Five randomised controlled trials were identified that presented evidence on diets
differing in the proportion of carbohydrate to fat on the insulin response to an
oral glucose tolerance test (Swinburn et al., 2001; Foster et al., 2003; Raatz et al.,
2005; Due et al., 2008a; Frisch et al., 2009). No further trials were identified in the
update search (Cardio-metabolic review, diabetes chapter).
5.103 Due to variation between the different methodologies used to measure fasting
insulin concentration, it was not possible to conduct a meta-analysis. Four trials
report no significant effect of diets differing in the proportion of carbohydrate
to fat on the insulin response to an oral glucose tolerance test. One trial reports
that a higher carbohydrate, lower fat diet lowered the insulin response to an oral
glucose tolerance test (Swinburn et al., 2001).
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Higher carbohydrate, lower fat diets and insulin response to oral glucose tolerance
test
• No effect
• Limited evidence
Insulin resistance/sensitivity
Higher carbohydrate and lower fat diets compared with lower
carbohydrate higher fat diets
5.104 Thirteen randomised controlled trials were identified that presented evidence on
diets differing in the proportion of carbohydrate to fat on measures of insulin
resistance/sensitivity (Helge, 2002; Wolever & Mehling, 2002; Foster et al., 2003;
Lofgren et al., 2005; Raatz et al., 2005; Johnston et al., 2006; Maki et al., 2007b;
Tinker et al., 2008; Due et al., 2008a; Grau et al., 2009; Kirk et al., 2009; Sacks et al.,
2009; de Luis et al., 2009a). Four trials were identified in the update search (Jebb et
al., 2010; Goree et al., 2011; Haufe et al., 2011; Shikany et al., 2011) (Cardio-metabolic
review, diabetes chapter; Update search). Shikany et al. (2011) reports data from the
same trial as Tinker et al. (2008) but over a longer time period.