Original Article

International Journal of Obesity (2016) 40, 305–311; doi:10.1038/ijo.2015.154; published online 8 September 2015

Clinical Studies and Practice

Effect of extended morning fasting upon ad libitum lunch intake and associated metabolic and hormonal responses in obese adults

E A Chowdhury1, J D Richardson1, K Tsintzas2, D Thompson1 and J A Betts1

  1. 1Department for Health, University of Bath, Bath, UK
  2. 2School of Life Sciences, Queen’s Medical Centre, University of Nottingham, Nottingham, England

Correspondence: Dr JA Betts, Department for Health, University of Bath, Bath BA2 7AY, UK. E-mail: J.Betts@bath.ac.uk

Received 12 May 2015; Revised 25 June 2015; Accepted 3 August 2015
Accepted article preview online 17 August 2015; Advance online publication 8 September 2015





Breakfast omission is positively associated with obesity and increased risk of disease. However, little is known about the acute effects of extended morning fasting upon subsequent energy intake and associated metabolic/regulatory factors in obese adults.



In a randomised cross-over design, 24 obese men (n=8) and women (n=16) extended their overnight fast by omitting breakfast consumption or ingesting a typical carbohydrate-rich breakfast of 2183±393kJ (521±94kcal), before an ad libitum pasta lunch 3h later. Blood samples were obtained throughout the day until 3h post lunch and analysed for hormones implicated in appetite regulation, along with metabolic outcomes and subjective appetite measures.



Lunch intake was unaffected by extended morning fasting (difference=218kJ, 95% confidence interval −54kJ, 490kJ; P=0.1) resulting in lower total intake in the fasting trial (difference=−1964kJ, 95% confidence interval −1645kJ, −2281kJ; P<0.01). Systemic concentrations of peptide tyrosine–tyrosine and leptin were lower during the afternoon following morning fasting (Pless than or equal to0.06). Plasma-acylated ghrelin concentrations were also lower following the ad libitum lunch in the fasting trial (P<0.05) but this effect was not apparent for total ghrelin (Pgreater than or equal to0.1). Serum insulin concentrations were greater throughout the afternoon in the fasting trial (P=0.05), with plasma glucose also greater 1h after lunch (P<0.01). Extended morning fasting did not result in greater appetite ratings after lunch, with some tendency for lower appetite 3h post lunch (P=0.09).



We demonstrate for the first time that, in obese adults, extended morning fasting does not cause compensatory intake during an ad libitum lunch nor does it increase appetite during the afternoon. Morning fasting reduced satiety hormone responses to a subsequent lunch meal but counterintuitively also reduced concentrations of the appetite-stimulating hormone-acylated ghrelin during the afternoon relative to lunch consumed after breakfast.

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