Carbohydrates and Health

2006; Noakes et al., 2006; Keogh et al., 2007; Meckling & Sherfey, 2007; Lasker
et al., 2008; Keogh et al., 2008; de Luis et al., 2009b). Two trials were identified in
the update search (Lim et al., 2010; Wood et al., 2012) (Cardio-metabolic review,
diabetes chapter; Update search).
5.95 No significant effect is demonstrated for diets differing in the proportion of
carbohydrate to fat and protein on fasting glucose concentration (0.02mmol/L,
95% CI -0.14, 0.17; p=0.84). 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 trials identified
in the update search report no significant effect of diets differing in the proportion
of carbohydrate to fat and protein on fasting glucose concentration.
Higher carbohydrate, lower fat, average protein diets and fasting blood glucose
concentration
• No effect
• Adequate evidence
Fasting blood insulin
Higher carbohydrate and lower fat diets compared with lower
carbohydrate higher fat diets
5.96 Thirty randomised controlled trials were identified that presented evidence on
diets differing in the proportion of carbohydrate to fat on fasting insulin (Peterson
& Jovanovic-Peterson, 1995; Racette et al., 1995; Golay et al., 1996; Golay et al.,
2000; Swinburn et al., 2001; Helge, 2002; Colette et al., 2003; Landry et al., 2003;
Lovejoy et al., 2003; Wolever & Mehling, 2003; Clifton et al., 2004; Cornier et al.,
2005; Dansinger et al., 2005; Lofgren et al., 2005; Petersen et al., 2006; Howard et
al., 2006b; Ebbeling et al., 2007; Gardner et al., 2007; Kirkwood et al., 2007; Maki
et al., 2007b; Phillips et al., 2008; Tinker et al., 2008; Due et al., 2008b; Dale et al.,
2009; Grau et al., 2009; Kirk et al., 2009; Morgan et al., 2009; Sacks et al., 2009;
Sloth et al., 2009; de Luis et al., 2009a). Five trials were identified in the update
search (Jebb et al., 2010; Goree et al., 2011; Haufe et al., 2011; Shikany et al., 2011;
Brooking et al., 2012) (Cardio-metabolic review, diabetes chapter ; Update search).
Shikany et al. (2011) presents the data from the same trial as Howard et al. (2006b)
but over a longer follow-up period.
5.97 Due to variation between the different methodologies used to measure fasting
insulin concentration, it was not possible to conduct a meta-analysis. Twenty four
trials report no significant effect of diets differing in the proportion of carbohydrate
to fat on fasting insulin; six trials do report an effect (Swinburn et al., 2001; Clifton
et al., 2004; Dansinger et al., 2005; Due et al., 2008b; Kirk et al., 2009; de Luis et
al., 2009a). One of these trials reports that the extent of weight loss predicts
the decrease in insulin concentration regardless of dietary group (Dansinger et
al., 2005). Nearly all trials employ energy restricted weight loss diets that vary
both carbohydrate (between 5% and 65% energy) and fat (between 18% and 40%
energy) between groups. It is not possible, therefore, to exclude confounding by
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