Abstract
Background/objective:Diet-induced weight loss (WL) leads to increased hunger and reduced fullness feelings, increased ghrelin and reduced satiety peptides concentration (glucagon-like peptide-1 (GLP-1), cholecystokinin (CCK) and peptide YY (PYY)). Ketogenic diets seem to minimise or supress some of these responses. The aim of this study was to determine the timeline over which changes in appetite occur during progressive WL with a ketogenic very-low-energy diet (VLED).Subjects/methods:Thirty-one sedentary adults (18 men), with obesity (body mass index: 37±4.5 kg m−2) underwent 8 weeks (wks) of a VLED followed by 4 wks of weight maintenance. Body weight and composition, subjective feelings of appetite and appetite-related hormones (insulin, active ghrelin (AG), active GLP-1, total PYY and CCK) were measured in fasting and postprandially, at baseline, on day 3 of the diet, 5 and 10% WL, and at wks 9 and 13. Data are shown as mean±s.d.Results:A significant increase in fasting hunger was observed by day 3 (2±1% WL), (P<0.01), 5% WL (12±8 days) (P<0.05) and wk 13 (17±2% WL) (P<0.05). Increased desire to eat was observed by day 3 (P<0.01) and 5% WL (P<0.05). Postprandial prospective food consumption was significantly reduced at wk 9 (16±2% WL) (P<0.01). Basal total PYY was significantly reduced at 10% WL (32±8 days) (P<0.05). Postprandial active GLP-1 was increased at 5% WL (P<0.01) and CCK reduced at 5 and 10% WL (P<0.01, for both) and wk 9 (P<0.001). Basal and postprandial AG were significantly increased at wk 13 (P<0.001, both).Conclusions:WL with a ketogenic VLED transiently increases the drive to eat up to 3 weeks (5% WL). After that, and while participants are ketotic, a 10–17% WL is not associated with increased appetite. However, hunger feelings and AG concentrations increase significantly from baseline, once refeeding occurs.
Highlights
Obesity has reached epidemic proportions worldwide and is associated with negative public health consequences and large socioeconomic costs.[1]
Males were heavier and with greater FFM than females (P o 0.01 and P o0.001, respectively), but there were no significant differences in age or BMI between sexes (Supplementary Table I )
Between 0.8 and 2.4 kg) report an increase in feelings of hunger, both in the fasting and postprandial state.[29,30,31,32]. These were not accompanied by changes in either active ghrelin (AG),[29] total ghrelin[31,32] or glucagon-like peptide-1 (GLP-1),29 which is in line with our findings
Summary
Obesity has reached epidemic proportions worldwide and is associated with negative public health consequences and large socioeconomic costs.[1]. An increase in ghrelin plasma concentration[13,14,15] and a reduction in the concentration of several satiety hormones, such as peptide YY (PYY), glucagon-like peptide-1 (GLP-1)[13,16,17,18] and cholecystokinin (CCK)[13,19] has been reported with diet-induced WL
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