Long-term effects of ad libitum low-fat, high-carbohydrate diets on body weight and serum lipids in overweight subjects with metabolic syndrome.
BACKGROUND
Overweight individuals with metabolic syndrome are at increased risk of type 2 diabetes and coronary vascular disease. Weight gain and features of the syndrome may be ameliorated by dietary intervention.


OBJECTIVE
We investigated the effects of replacing one-quarter of daily fat intake by complex or simple carbohydrate on body weight and intermediary metabolism.


METHODS
Forty-six subjects with > or =3 metabolic syndrome risk factors were randomly assigned to receive a control diet; a low-fat, complex carbohydrate diet (LF-CC); or a low-fat, simple carbohydrate diet (LF-SC) for 6 mo. Thirty-nine subjects completed the trial. About 60% of daily dietary intake was provided free of charge through a grocery store. Energy intake was ad libitum. Body weight, body mass index (BMI), blood pressure, and blood lipids were measured at months 0, 2, 4, and 6.


RESULTS
There was a significant diet x time interaction on body weight and BMI (P < 0.001). Weight loss was greatest with the LF-CC diet [change in body weight: control diet, 1.03 kg (NS); LF-CC diet, -4.25 kg (P < 0.01); LF-SC diet, -0.28 kg (NS)]. Total cholesterol decreased by 0.33 mmol/L, 0.63 mmol/L, and 0.06 mmol/L in subjects consuming the control, LF-CC, and LF-SC diets, respectively (difference between the LF-CC and LF-SC groups: P < 0.05). There were no significant changes in LDL cholesterol, whereas HDL cholesterol decreased over time in all 3 groups (P < 0.0001). Triacylglycerol concentrations were higher in the LF-SC group than in the other 2 groups (P < 0.05).


CONCLUSIONS
A low-fat, high-polysaccharide diet in overweight individuals with abnormal intermediary metabolism led to moderate weight loss and some improvement in serum cholesterol. Increasing simple carbohydrates did not promote weight gain, but nor was there improvement in body weight or lipid profile.
Poppitt
Sally D
SD
MRC Dunn Clinical Nutrition Centre, Cambridge, United Kingdom. s.poppitt@auckland.ac.nz
Keogh
Geraldine F
GF
Prentice
Andrew M
AM
Williams
Desmond E M
DE
Sonnemans
Heidi M W
HM
Valk
Esther E J
EE
Robinson
Elizabeth
E
Wareham
Nicholas J
NJ
D000328:Adult; D001794:Blood Pressure / Q000187:drug effects; D015992:Body Mass Index; D001835:Body Weight / Q000187:drug effects; D004040:Dietary Carbohydrates / Q000008:administration & dosage* / Q000494:pharmacology; D004041:Dietary Fats / Q000008:administration & dosage* / Q000494:pharmacology; D002149:Energy Intake; D005260:Female; D006801:Humans; D008055:Lipids / Q000097:blood*; D008297:Male; D024821:Metabolic Syndrome; D008875:Middle Aged; D009765:Obesity / Q000178:diet therapy*; D012307:Risk Factors
D004040:Dietary Carbohydrates; D004041:Dietary Fats; D008055:Lipids