Most systematic review s and meta-analyses from controlled feeding trials have shown that fructose-containing sugars in isocaloric exchange for other carbohydrates do not show evidence of harm and , in the case of fructose , may even have advantages for glycaemic control , especially at small doses .
Nevertheless , trials in which fructose-containing sugars supplement diets with excess energy have shown adverse effects , effects that appear more attributable to the excess energy than the sugar .
There is no unequivocal evidence that fructose intake at moderate doses is directly related with adverse metabolic effects , although there is potentially cause for concern where fructose is provided at high doses or contributes excess energy to diets .
Concerns are growing regarding the role of dietary sugars in the development of obesity and cardiometabolic diseases , including diabetes .
High-fructose corn syrup ( HFCS ) and sucrose are the most important dietary sweeteners .
Both HFCS and sucrose have overlapping metabolic actions with adverse effects attributed to their fructose moiety .
Ecological studies have linked the rise in fructose availability with the increases in obesity and diabetes worldwide .
This link has been largely underpinned by animal models and select human trials of fructose overfeeding at high levels of exposure .
Effects of 4 weight-loss diets differing in fat, protein, and carbohydrate on fat mass, lean mass, visceral adipose tissue, and hepatic fat: results from the POUNDS LOST trial.
BACKGROUND Weight loss reduces body fat and lean mass , but whether these changes are influenced by macronutrient composition of the diet is unclear . OBJECTIVE We determined whether energy-reduced diets that emphasize fat , protein , or carbohydrate differentially reduce total , visceral , or hepatic fat or preserve lean mass . DESIGN In a subset of participants in a r and omized trial of 4 weight-loss diets  , body fat and lean mass ( n = 424 ; by using dual-energy X-ray absorptiometry ) and abdominal and hepatic fat ( n = 165 ; by using computed tomography ) were measured after 6 mo and 2 y. Changes from baseline were compared between assigned amounts of protein ( 25 % compared with 15 % ) and fat ( 40 % compared with 20 % ) and across 4 carbohydrate amounts ( 35 % through 65 % ) . RESULTS At 6 mo , participants lost a mean ( ±SEM ) of 4.2 ± 0.3 kg ( 12.4 % ) fat and 2.1 ± 0.3 kg ( 3.5 % ) lean mass ( both P < 0.0001 compared with baseline values ) , with no differences between 25 % and 15 % protein ( P ≥ 0.10 ) , 40 % and 20 % fat ( P ≥ 0.34 ) , or 65 % and 35 % carbohydrate ( P ≥ 0.27 ) . Participants lost 2.3 ± 0.2 kg ( 13.8 % ) abdominal fat : 1.5 ± 0.2 kg ( 13.6 % ) subcutaneous fat and 0.9 ± 0.1 kg ( 16.1 % ) visceral fat ( all P < 0.0001 compared with baseline values ) , with no differences between the diets ( P ≥ 0.29 ) . Women  lost more visceral fat than did men relative to total-body fat loss . Participants regained ~40 % of these losses by 2 y , with no differences between diets ( P ≥ 0.23 ) . Weight loss reduced hepatic fat , but there were no differences between groups ( P ≥ 0.28 ) . Dietary goals were not fully met ; self-reported contrasts were closer to 2 % protein , 8 % fat , and 14 % carbohydrate at 6 mo and 1 % , 7 % , and 10 % , respectively , at 2 y. CONCLUSION Participants lost more fat than lean mass after consumption of all diets , with no differences in changes in body composition , abdominal fat , or hepatic fat between assigned macronutrient amounts . This trial was registered at clinical trials.gov as NCT00072995
Most systematic review s and meta-analyses from controlled feeding trials have shown that fructose-containing sugars in isocaloric exchange for other carbohydrates do not show evidence of harm and , in the case of fructose , may even have advantages for glycaemic control , especially at small doses .
Nevertheless , trials in which fructose-containing sugars supplement diets with excess energy have shown adverse effects , effects that appear more attributable to the excess energy than the sugar .
There is no unequivocal evidence that fructose intake at moderate doses is directly related with adverse metabolic effects , although there is potentially cause for concern where fructose is provided at high doses or contributes excess energy to diets .
Concerns are growing regarding the role of dietary sugars in the development of obesity and cardiometabolic diseases , including diabetes .
High-fructose corn syrup ( HFCS ) and sucrose are the most important dietary sweeteners .
Both HFCS and sucrose have overlapping metabolic actions with adverse effects attributed to their fructose moiety .
Ecological studies have linked the rise in fructose availability with the increases in obesity and diabetes worldwide .
This link has been largely underpinned by animal models and select human trials of fructose overfeeding at high levels of exposure .