Comparison of surgical versus diet‐induced weight loss on appetite regulation and metabolic health outcomes

Abstract

Bariatric surgery is associated with significant and sustained weight loss and improved metabolic outcomes. It is unclear if weight loss alone is the main mechanism of improved metabolic health. The purpose of this trial was to compare indices of appetite regulation, insulin sensitivity and energy intake ( EI ) between participants achieving 10 kg of weight loss via Roux‐en‐Y Gastric Bypass ( RYGB ) or dietary restriction ( DIET ); intake of a very low calorie liquid diet (800 kcal/d; 40% protein, 40% fat, 20% carbohydrate that matched the post‐ RYGB dietary protocol). Adults qualifying for bariatric surgery were studied before and after 10 kg of weight loss ( RYGB [ n = 6]) or DIET [ n = 17]). Appetite (hunger, satiety, and prospective food consumption [ PFC ]), appetite–related hormones, and metabolites (ghrelin, PYY , GLP ‐1, insulin, glucose, free fatty acids [ FFA ], and triglycerides [ TG ]) were measured in the fasting state and every 30 min for 180 min following breakfast. Participants were provided lunch to evaluate acute ad libitum EI , which was similarly reduced in both groups from pre to post weight loss. Fasting ghrelin was reduced to a greater extent following RYGB compared to DIET ( P = 0.04). Area under the curve ( AUC ) for ghrelin ( P = 0.01), hunger ( P < 0.01) and PFC ( P < 0.01) increased after DIET compared to RYGB , following 10 kg weight loss. Satiety AUC increased after RYGB and decreased after DIET ( P < 0.01). Glucose and insulin (fasting and AUC ) decreased in both groups. FFA increased in both groups, with a greater increase in AUC seen after RYGB versus DIET ( P = 0.02). In summary, appetite–related indices were altered in a manner that, if maintained, may promote a sustained reduction in energy intake with RYGB compared to DIET . Future work with a larger sample size and longer follow‐up will be important to confirm and extend these findings.

Does a Higher Protein Diet Promote Satiety and Weight Loss Independent of Carbohydrate Content? An 8-Week Low-Energy Diet (LED) Intervention

“…The DIOGENES sub-study reported no change in fasting Hunger, but the AUC Hunger decreased by 18% following LED intervention [ 54 ]. Following VLED interventions, Lyngstad et al [ 55 ] reported an increase in fasting Hunger and a decrease in postprandial Hunger, similar to our findings; Adam et al [ 56 ], Sumithran et al [ 57 ], and Nymo et al [ 58 ] reported no change in both fasting and postprandial Hunger; whereas Halliday et al [ 59 ] reported a decrease in fasting Hunger but an increase in postprandial Hunger. One likely explanation for the difference in appetite responses is the state of ketosis during the negative energy balance.…”

Plasma Free Fatty Acid Concentration as a Modifiable Risk Factor for Metabolic Disease

“…In some studies of weight loss from bariatric surgery [ 87 , 88 , 89 , 90 ] and CR from dietary intervention [ 91 , 92 ], plasma FFA concentration was reported to be lower after weight loss as compared to plasma from the same individuals before weight loss. In other longitudinal studies (also without weight-stable control groups), this decline of plasma FFA concentration with weight loss from bariatric surgery [ 25 , 93 ] or dietary intervention [ 93 ] was not observed. Results are mixed but seem to favor the likelihood of a reduced plasma FFA with weight loss.…”

Editorial: Mechanisms Linking Transport and Utilization of Metabolic Fuels to the Impact of Nutrition and Exercise Upon Health

“…One intriguing suggestion by the authors was that the elevated fat oxidation occurring from free fatty acid (FFA) utilization during (or after) exercise (2, 3) might lead to enhanced acetyl-CoA availability for use as a substrate for histone acetylation. Future work could lead to a greater understanding of the implications of elevated plasma FFA abundance and utilization during and after exercise (2,4) and in negative energy balance (5).…”