Methods of determining energy balance using breath carbon isotope ratios

Abstract

Described herein are methods of determining energy balance in individuals such as exercising individuals, individuals consuming a 13 C-enriched test composition and individuals consuming a fixed diet with a known δ 13 C. The δ 13 C pre- and post-exercise, or pre- and post-consumption of the test beverage or fixed diet indicate whether the individual is in neutral or positive energy balance, or in energy deficit. The methods are particularly useful for individuals participating in weight management programs, and individuals under the care of health care professionals.

1 . A method of determining energy balance in an exercising individual, comprising
 obtaining a pre-exercise breath sample from the individual,   exercising the individual for a period of time,   obtaining a post-exercise breath sample from the individual, and   determining a δ 13 C of the pre-exercise breath sample and a δ 13 C of the post-exercise breath sample,   wherein an increased post-exercise δ 13 C compared to the pre-exercise δ 13 C indicates that the individual is at neutral or positive energy balance, and a substantially constant post-exercise δ 13 C compared to the pre-exercise δ 13 C indicates that the individual is in energy deficit.   
     
     
         2 . The method of  claim 1 , wherein the increased post-exercise δ 13 C is greater than or equal to 0.7‰ during neutral or positive energy balance, and the substantially constant post-exercise δ 13 C is increased less than 0.7‰ in energy deficit. 
     
     
         3 . The method of  claim 1 , wherein the individual is a participant in a weight-loss program consuming an energy-restricted diet. 
     
     
         4 . The method of  claim 3 , wherein the individual is in weight maintenance, and recommending a reduction in calorie intake or an increase in exercise. 
     
     
         5 . The method of  claim 1 , wherein the exercise intensity is aerobic and less than one hour. 
     
     
         6 . The method of  claim 1 , wherein the individual is in need of body mass increase and is consuming an energy-excess diet. 
     
     
         7 . The method of  claim 6 , wherein the individual is in energy deficit, and recommending an increase in calorie intake or a decrease in exercise. 
     
     
         8 . A method of determining energy balance in an individual, comprising
 obtaining a pre-test breath sample from the individual,   administering a  13 C-enriched test composition to the subject, wherein a δ 13 C of the  13 C-enriched test composition is increased relative to a δ 13 C of the pre-test breath sample,   obtaining a post-test breath sample from the individual within 0.25 to 6 hours of administering the  13 C-enriched test composition, and   determining the δ 13 C of the pre-test breath sample and a δ 13 C of the post-test breath sample,   wherein an increased post-test δ 13 C compared to the pre-test δ 13 C indicates that the individual is in neutral or positive energy balance, and a substantially constant post-test δ 13 C compared to the pre-test δ 13 C indicates that the individual is in energy deficit.   
     
     
         9 . The method of  claim 8 , wherein the δ 13 C of the  13 C-enriched test composition is known. 
     
     
         10 . The method of  claim 8 , wherein the increased post-test δ 13 C is greater than or equal to 0.7‰ during neutral or positive energy balance, and the substantially constant post-test δ 13 C is increased less than 0.7‰ in energy deficit. 
     
     
         11 . The method of  claim 8 , wherein the individual is a patient under the care of health personnel. 
     
     
         12 . The method of  claim 11 , wherein the human individual is a human individual in terminal care; an individual receiving intragastric or intraparenteral nutrition; an individual undergoing cancer treatment; an individual in elder care; an individual with AIDS; an individual in convalescence following trauma, surgery or burn; or an individual with an eating disorder. 
     
     
         13 . The method of  claim 11 , wherein the individual is a patient in an intensive care unit or a neonate in a neonatal care unit. 
     
     
         14 . The method of  claim 13 , wherein the individual is subject to intragastric feeding or total intraparenteral nutrition. 
     
     
         15 . The method of  claim 14 , wherein the individual is in an energy deficit, and the method further comprises increasing the rate of gastric and/or parenteral feeding. 
     
     
         16 . The method of  claim 8 , wherein the human individual is a subject in a human study in which dietary compliance is determined or monitored. 
     
     
         17 . The method of  claim 8 , wherein the  13 C-enriched test composition is a liquid sweetened with cane sugar, corn sugar, or corn oil. 
     
     
         18 . A method of determining energy balance in an individual consuming a fixed diet with a known δ 13 C, comprising
 the individual consuming the fixed diet with known δ 13 C on a first day, wherein the δ 13 C of the fixed diet is increased relative to a δ 13 C of the individual's breath, and wherein the fixed diet includes at least a first meal and a second meal, 
 obtaining a first day breath sample from the individual, 
 obtaining a second day breath sample from the individual, 
 wherein the first day breath sample and the second day breath sample are taken at approximately the same time of day and about 24 hours apart, and 
 determining a first day breath sample δ 13 C and a second day breath sample δ 13 C, 
 wherein an increased second day δ 13 C compared to the first day δ 13 C indicates that the individual is in neutral or positive energy balance, and a substantially constant second day δ 13 C compared to the first day δ 13 C indicates that the individual is in energy deficit. 
 
     
     
         19 . The method of  claim 18 , wherein the individual is an agricultural animal. 
     
     
         20 . The method of  claim 19 , wherein the agricultural animal is selected from cattle, swine, horses, sheep, chickens, ducks, turkeys, pheasants, and fish. 
     
     
         21 . The method of  claim 18 , wherein the individual is a domesticated pet. 
     
     
         22 . The method of  claim 21 , wherein the pet is selected from dogs and cats. 
     
     
         23 . The method of  claim 18 , wherein the individual is a human and the increased second day δ 13 C, when compared to the first day δ 13 C is at least 0.7‰ during neutral or positive energy balance, and the substantially constant δ 13 C from the first day to the second day is less than 0.7‰ in energy deficit. 
     
     
         24 . The method of  claim 18 , wherein the individual is a human individual in terminal care; an individual receiving intragastric or intraparenteral nutrition; an individual undergoing cancer treatment; an individual in elder care, an individual with AIDS; an individual in convalescence following trauma, surgery or burn; or an individual with an eating disorder. 
     
     
         25 . The method of  claim 18 , wherein the individual is a subject in a human study in which dietary compliance is determined or monitored. 
     
     
         26 . The method of  claim 18 , where the individual is a human individual adhering to a weight loss diet regimen.