Role of nutritional ketosis in the improvement of metabolic parameters following bariatric surgery

Table 1 Pre-operative patient characteristics

	All 39	Missing
Age, yr	46.5 ± 9.0	-
Male, n (%)	10 (25.6)	-
Hypertension, n (%)	17 (43.6)	-
Diabetes mellitus, n (%)	9 (23.1)	-
Dyslipidaemia, n (%)	22 (56.4)	-
MAFLD	29 (74.4)	-
Waist circumference (cm)		2
Males	129.7 ± 6.2
Females	114.1 ± 13.3
BMI, kg/m2	41.0 (38.5; 45.4)	-
Fat mass (%)	45.2 ± 6.2	5
Plasma glucose (mg/dL)	91.0 (84.0; 98.3)	1
Total cholesterol (mg/dL)	193.1 ± 29.6	3
HDL cholesterol (mg/dL)	48.0 (42.0; 58.0)	4
LDL cholesterol (mg/dL)	115.1 ± 28.0	4
Triglycerides (mg/dL)	118.5 (102.3; 159.3)	3

MAFLD: Metabolic-associated fatty liver disease; BMI: Body mass index; HbA1c: Glycated haemoglobin; HDL: High-density lipoprotein; LDL: Low-density lipoprotein.

Table 2 Comparison of pre-operative characteristics between subjects who developed (patients with post-operative ketosis) or did not develop (patients without post-operative ketosis) ketosis after surgery

	KB+ (n = 27)	KB- (n = 12)	P value
Age, yr	42.9 (37.6; 50.7)	51.9 (48.3; 59.9)	0.018
Female, n (%)	20 (74.1)	9 (75.0)	1.000
Hypertension, n (%)	11 (40.7)	6 (50.0)	0.730
Diabetes mellitus, n (%)	4 (14.8)	5 (41.7)	0.102
Dyslipidaemia, n (%)	14 (51.9)	8 (66.7)	0.494
MAFLD	20 (74.1)	9 (75.0)	0.683
Waist circumference1 (cm)	119.3 ± 13.5	115.3 ± 14.0	0.421
BMI, kg/m2	41.0 (38.7; 45.4)	40.1 (35.9; 45.6)	0.663
Fat mass (%)	45.6 ± 6.2	44.2 ± 6.1	0.552
Plasma glucose (mg/dL)	89.5 (82.5; 96.3)	96.0 (91.0; 105.3)	0.025
HbA1c (mmol/mol)	37.0 (35.8; 41.0)	38.5 (36.0; 46.3)	0.305
Total cholesterol (mg/dL)	197.1 ± 25.8	183.9 ± 36.4	0.222
HDL cholesterol (mg/dL)	48.0 (42.5; 53.0)	49.0 (39.5; 62.0)	0.843
LDL cholesterol (mg/dL)	121.0 ± 23.5	100.2 ± 33.9	0.045
Triglycerides (mg/dL)	108.0 (84.5; 152.5)	152.0 (124.0; 186.0)	0.020

¹Pooled data for males and females, as there were only 2 males in the patients without post-operative ketosis group.

MAFLD: Metabolic-associated fatty liver disease; BMI: Body mass index; HbA1c: Glycated haemoglobin; HDL: High-density lipoprotein; LDL: Low-density lipoprotein; KB: Ketone bodies; WL: Weight loss.

Table 3 Hierarchical regression analysis for weight loss at 6 mo

	Weight loss at 6 mo
	Model 1		Model 2		Model 3
Variable	B	β	B	β	B	β
Constant	30.300b		22.386b		16.984
Age	-0.106	-0.186	-0.113	-0.199	-0.032	-0.057
Sex (male)	4.038a	0.305	3.756a	0.325	4.391a	0.380
BMI			0.200	0.201	0.203	0.204
Urinary KB					0.074a	0.365
R2	0.157		0.196		0.307
F	3.351a		2.852		3.759a
ΔR2	0.157		0.040		0.110
ΔF	3.351a		1.722		5.402a

^aP < 0.05.

^bP < 0.01.

BMI: Body mass index; KB: Ketone bodies.