There was interaction by food source , with specific food sources showing beneficial effects ( fruit and fruit juice ) or harmful effects ( sweetened milk and mixed sources ) in substitution studies and harmful effects ( sugars‐sweetened beverages and fruit juice ) in addition studies on at least one outcome .
Conclusions Energy control and food source appear to mediate the effect of fructose‐containing sugars on glycaemic control .
Although most food sources of these sugars ( especially fruit ) do not have a harmful effect in energy matched substitutions with other macronutrients , several food sources of fructose‐containing sugars ( especially sugars‐sweetened beverages ) adding excess energy to diets have harmful effects .
Objective To assess the effect of different food sources of fructose‐containing sugars  on glycaemic control at different levels of energy control .
Reformulating cereal bars: high resistant starch reduces in vitro digestibility but not in vivo glucose or insulin response; whey protein reduces glucose but disproportionately increases insulin.
BACKGROUND Resistant starch ( RS ) and whey protein are thought to be effective nutrients for reducing glycemic responses . OBJECTIVE We aim ed to determine the effect of varying the sucrose , RS , and whey protein content of cereal bars on glucose and insulin responses . DESIGN Twelve healthy subjects [ mean ± SD age : 36 ± 12 y ; mean ± SD body mass index ( in kg/m2 ) : 24.9 ± 2.7 ] consumed 40 g available-carbohydrate ( avCHO ) portions of 5 whole-grain cereal bars that contained varying amounts of RS and whey protein concentrate [ WPC ; 70 % protein ; RS : WPC , % wt : wt : 15:0 ( Bar15/0 ) ; 15:0 , low in sucrose ( Bar15/0LS ) ; 15:5 ( Bar15/5 ) ; 10:5 ( Bar10/5 ) ; and 10:10 ( Bar10/10 ) ] and 2 portion sizes of a control bar low in whole grains , protein , and RS [ control 1 contained 40 g avCHO ( Control1 ) ; control 2 contained total carbohydrate equal to Bar15/0LS ( Control2 ) ] on separate days by using a r and omized crossover design . Glucose and insulin responses in vivo and carbohydrate digestibility in vitro were measured over 3 h. RESULTS Incremental area under the curve ( iAUC ) over 0 - 3 h for glucose ( min × mmol/L ) differed significantly between treatments ( P < 0.001 ) [ Bar15/0LS ( mean ± SEM ) , 169 ± 14 ; Control2 , 164 ± 20 ; Bar15/0 , 144 ± 15 ; Control1 , 140 ± 17 ; Bar10/5 , 117 ± 12 ; Bar15/5 , 116 ± 9 ; and Bar10/10 , 100 ± 9 ; Tukey 's least significant difference = 42 , P < 0.05 ] , but insulin iAUC did not differ significantly . Higher protein content was associated with a lower glucose iAUC ( P = 0.028 ) and a higher insulin-to-glucose iAUC ratio ( P = 0.002 ) All 5 RS-containing bars were digested in vitro ∼30 % more slowly than the control bars ( P < 0.05 ) ; however , in vivo responses were not related to digestibility in vitro . Glucose and insulin responses elicited by high-RS , whey protein-free bars were similar to those elicited from control bars . CONCLUSIONS The inclusion of RS in cereal bar formulations did not reduce glycemic responses despite slower starch digestion in vitro . Thus , caution is required when extrapolating in vitro starch digestibility to in vivo glycemic response . The inclusion of whey protein in cereal bar formulations to reduce glycemic response requires caution because this may be associated with a disproportionate increase in insulin as judged by an increased insulin-to-glucose iAUC ratio . This trial was registered at clinical trials.gov as NCT02537587
There was interaction by food source , with specific food sources showing beneficial effects ( fruit and fruit juice ) or harmful effects ( sweetened milk and mixed sources ) in substitution studies and harmful effects ( sugars‐sweetened beverages and fruit juice ) in addition studies on at least one outcome .
Conclusions Energy control and food source appear to mediate the effect of fructose‐containing sugars on glycaemic control .
Although most food sources of these sugars ( especially fruit ) do not have a harmful effect in energy matched substitutions with other macronutrients , several food sources of fructose‐containing sugars ( especially sugars‐sweetened beverages ) adding excess energy to diets have harmful effects .
Objective To assess the effect of different food sources of fructose‐containing sugars  on glycaemic control at different levels of energy control .