A method for determining whether a subject is at risk of developing a digestive system disease; wherein the method comprises determining in a biological sample obtained from the subject a quantitative value of at least one biomarker of the following in the biological sample: - glycoprotein acetyls, - albumin, - ratio of docosahexaenoic acid to total fatty acids, - ratio of linoleic acid to total fatty acids, - ratio of monounsaturated fatty acids and/or of oleic acid to total fatty acids, - ratio of omega-3 fatty acids to total fatty acids, - ratio of omega-6 fatty acids to total fatty acids, - fatty acid degree of unsaturation, - docosahexaenoic acid, - linoleic acid, - monounsaturated fatty acids and/or oleic acid, - omega-3 fatty acids, - omega-6 fatty acids, - triglycerides in high-density lipoprotein, - triglycerides in intermediate-density lipoprotein, - triglycerides in low-density lipoprotein, - triglycerides in very-low-density lipoprotein (VLDL), - high-density lipoprotein particle size, - low-density lipoprotein particle size, - very-low-density lipoprotein (VLDL) particle size, - acetate, - citrate, - creatinine, - glutamine, - glycine, - isoleucine, - phenylalanine; and comparing the quantitative value(s) of the at least one biomarker to a control sample or to a control value; wherein an increase or a decrease in the quantitative value(s) of the at least one biomarker, when compared to the control sample or to the control value, is/are indicative of the subject having an increased risk of developing the digestive system disease; wherein the at least one biomarker comprises or is glycoprotein acetyls, wherein glycoprotein acetyls refers to a nuclear magnetic resonance spectroscopy signal that represents the abundance of circulating glycated proteins; and wherein the digestive system disease is cholelithiasis (ICD-10 diagnosis code K80); cholecystitis (ICD-10 diagnosis code K81); and/or other disease of gallbladder (ICD-10 diagnosis code K82). wherein the method comprises determining in a biological sample obtained from the subject a quantitative value of at least one biomarker of the following in the biological sample: - glycoprotein acetyls, - albumin, - ratio of docosahexaenoic acid to total fatty acids, - ratio of linoleic acid to total fatty acids, - ratio of monounsaturated fatty acids and/or of oleic acid to total fatty acids, - ratio of omega-3 fatty acids to total fatty acids, - ratio of omega-6 fatty acids to total fatty acids, - fatty acid degree of unsaturation, - docosahexaenoic acid, - linoleic acid, - monounsaturated fatty acids and/or oleic acid, - omega-3 fatty acids, - omega-6 fatty acids, - triglycerides in high-density lipoprotein, - triglycerides in intermediate-density lipoprotein, - triglycerides in low-density lipoprotein, - triglycerides in very-low-density lipoprotein (VLDL), - high-density lipoprotein particle size, - low-density lipoprotein particle size, - very-low-density lipoprotein (VLDL) particle size, - acetate, - citrate, - creatinine, - glutamine, - glycine, - isoleucine, - phenylalanine; and - glycoprotein acetyls, - albumin, - ratio of docosahexaenoic acid to total fatty acids, - ratio of linoleic acid to total fatty acids, - ratio of monounsaturated fatty acids and/or of oleic acid to total fatty acids, - ratio of omega-3 fatty acids to total fatty acids, - ratio of omega-6 fatty acids to total fatty acids, - fatty acid degree of unsaturation, - docosahexaenoic acid, - linoleic acid, - monounsaturated fatty acids and/or oleic acid, - omega-3 fatty acids, - omega-6 fatty acids, - triglycerides in high-density lipoprotein, - triglycerides in intermediate-density lipoprotein, - triglycerides in low-density lipoprotein, - triglycerides in very-low-density lipoprotein (VLDL), - high-density lipoprotein particle size, - low-density lipoprotein particle size, - very-low-density lipoprotein (VLDL) particle size, - acetate, - citrate, - creatinine, - glutamine, - glycine, - isoleucine, - phenylalanine; and comparing the quantitative value(s) of the at least one biomarker to a control sample or to a control value; wherein an increase or a decrease in the quantitative value(s) of the at least one biomarker, when compared to the control sample or to the control value, is/are indicative of the subject having an increased risk of developing the digestive system disease; wherein the at least one biomarker comprises or is glycoprotein acetyls, wherein glycoprotein acetyls refers to a nuclear magnetic resonance spectroscopy signal that represents the abundance of circulating glycated proteins; and wherein the digestive system disease is cholelithiasis (ICD-10 diagnosis code K80); cholecystitis (ICD-10 diagnosis code K81); and/or other disease of gallbladder (ICD-10 diagnosis code K82).