Research paper
Sumithran P, Prendergast LA, Delbridge E, Purcell K, Shulkes A, Kriketos A, Proietto J. Long-term persistence of hormonal adaptations to weight loss. N Engl J Med. 2011;365(17):1597-1604.
Why we cite it
Measured nine appetite-regulating hormones in 50 overweight or obese patients without diabetes, at baseline, after a 10-week very-low-energy diet (550 kcal/day, mean loss 13.5 ± 0.5 kg), and again at week 62. Directly relevant to the project because seven of the nine still differed significantly from baseline one year on — leptin, peptide YY, CCK, insulin, ghrelin, GIP and pancreatic polypeptide — and subjective appetite ratings were still higher (P<0.001). GLP-1 and amylin did not persist, so the count of hormones measured and the count that lasted are not the same number. The design is single-arm: no control group, and week 62 is compared against these same patients' own baseline. It establishes that the changes persist; it does not show that the persistence caused regain, and no participant's regain was tested against their own hormone profile. It is the project's primary source for hormonal adaptation as a barrier to sustained weight loss.