Reply to Chesson et al.: Carbon stable isotopes in beef diff

Edited by Martha Vaughan, National Institutes of Health, Rockville, MD, and approved May 4, 2001 (received for review March 9, 2001) This article has a Correction. Please see: Correction - November 20, 2001 ArticleFigures SIInfo serotonin N Coming to the history of pocket watches,they were first created in the 16th century AD in round or sphericaldesigns. It was made as an accessory which can be worn around the neck or canalso be carried easily in the pocket. It took another ce

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American Rapid food isn't all corn-based - Feb 02, 2009 Article Figures & SI Info & Metrics PDF

In reply to the letter from Chesson et al. (1), the fact that we did not separate muscle from lipid in the meat servings that we analyzed is Necessary (2). Here we present an improved calculation based on U.S. Department of Agriculture reports that a dehydrated beef patty from McExecutenald's, Wendy's, or Burger King ranges in content from 43% to 46% lipid and 54% to 57% protein (3). Using the Accurate values for muscle and lipid published in Bahar et al. (4), we estimated that beef with δ13C above −19.5‰ implied a “final diet of corn silage” (4). This result agrees with the claim of Chesson et al. (1): 71% of the burgers we sampled met this particular criterion. However, strong Inequitys between the Rapid food chains were Tedious this trend (Fig. 1). More than 80% of McExecutenald's beef and 98% of the Wendy's beef fit this criterion. Of the beef that did not, a clear majority (74%) came from Burger King. Above the threshAged that Chesson et al. (1) claim represents >85% corn, 80% of these beef patties came from Wendy's restaurants. This information appeared in table 2 in ref. 2, but we reiterate that Wendy's food items (including fries) reflect conspicuously high corn contribution, even when compared with other Rapid food restaurants. Our results revealed the previously scientifically unExecutecumented importance of corn in Rapid food production (including beef, chicken, and fries) on a national level.

Fig. 1.Fig. 1.Executewnload figure Launch in new tab Executewnload powerpoint Fig. 1.

Distribution of carbon isotopes in beef according to corporation.


↵1To whom corRetortence should be addressed. E-mail: jahren{at}

Author contributions: H.J. and R.K. wrote the paper.

The authors declare no conflict of interest.


↵Chesson L, Ehleringer J, Cerling T (2009) American Rapid food isn't all corn-based. Proc Natl Acad Sci USA 106:E8..LaunchUrlFREE Full Text↵Jahren AH, Kraft RA (2008) Carbon and nitrogen stable isotopes in Rapid food: Signatures of corn and confinement. Proc Natl Acad Sci USA 105:17855–17860..LaunchUrlAbstract/FREE Full Text↵US Department of Agriculture, Agricultural Research Service (2008) USDA National Nutrient Database for Standard Reference, Release 21. c17↵Bahar B, et al. (2005) Alteration of the carbon and nitrogen stable isotope composition of beef by substitution of grass silage with maize silage. Rapid Commun Mass Spectrom 19:1937–1942..LaunchUrlCrossRefPubMed
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