Research report Energy and macronutrient composition of breakfast affect gastric emptying of lunch and subsequent food intake, satiety and satiation Miriam Clegg a,b , Amir Shafat a, * a University of Limerick, Limerick, Ireland b Functional Food Centre, School of Life Sciences, Oxford Brookes University, Gipsy Lane, Oxford, OX3 0BP, UK Introduction The obesity epidemic escalated from about 1980 and has been rising relentlessly ever since (James, 2008). Overconsumption of high-energy-dense food is among the contributors to positive energy balance (Rolls, 2000). Studies suggest there is a hierarchy in the potency of macronutrient satiation, with protein being the most satiating and fat the least. However, a major limitation of many of these studies is that when fat is added to the meal, the meal is controlled for mass but not for energy content (Sepple & Read, 1990) or vice versa (Blundell, Burley, Cotton, & Lawton, 1993; Foltin, Rolls, Moran, Kelly, & McNelis, 1992; Holt, Delargy, Lawton, & Blundell, 1999; Johnson & Vickers, 1993; Poortvliet, Berube- Parent, Drapeau, Lamarche, & Blundell, 2007). Nevertheless, a few studies do take meal mass into consideration (de Graaf, Hulshof, Weststrate, & Jas, 1992; Rolls, Kim-Harris, Fischman, Foltin, & Moran, 1994). One of these studies found that fat reduces food intake from a test meal less than carbohydrate or protein (Rolls et al., 1994), while the other found no difference in the satiating effects of macronutrients (de Graaf et al., 1992). It is still unclear whether fat is able to induce satiation (sensations leading to meal termination) and satiety (sensation preventing the onset of a new meal or eating bout) to a greater or lesser extent than other macronutrients. The term gastric emptying (GE) refers to the rate at which food empties from the stomach. It is established in the extant literature that eating meals of a larger mass (weight) yet of equal kilocalorie content leads to longer GE times (Moore, Christian, & Coleman, 1981; Moore, Christian, Brown, Brophy, & Datz, 1984) yet faster GE rates (Moore et al., 1981, 1984). Increasing the calorie content of the meal also significantly lengthens GE times (Gonlachanvit, Chey, Goodman, & Parkman, 2001; Hunt & Stubbs, 1975; Moore et al., 1984; Peracchi, Gebbia, Ogliari, Fraquelli, & Vigano, 2000; Urbain, Siegel, Mortelmans, van Cutsem, & van den Maegdenbergh, 1989; Velchik, Reynolds, & Alavi, 1989). The effect of fat on GE is already well established. When high-fat (HF) and low-fat (LF) soups of equal mass, volume and energy content (1999) were ingested orally, the HF soup slowed GE. GE also plays an important role in the control of gastric distention, supply of nutrients to the small intestine and hence satiety. A significant correlation has also been found between the time for 90% of the meal to empty from the stomach and the postprandial increase in hunger ratings (r = 0.75) (Sepple & Read, 1989). In this study hunger ratings started to increase in three subjects when over 40% of the food still remained Appetite xxx (2010) xxx–xxx ARTICLE INFO Article history: Received 7 July 2009 Received in revised form 27 January 2010 Accepted 9 February 2010 Keywords: Gastric emptying Satiety Fat Breakfast Sodium [ 13 C] acetate breath test Meal mass ABSTRACT Satiety and food intake are closely related to gastrointestinal transit and specifically gastric emptying. High-fat (HF) meals empty more slowly from the stomach yet are less satiating than isoenergetic low-fat (LF) meals. The current study examines how gastric emptying and satiety at lunch are affected by energy and macronutrient content of breakfast. Nine male volunteers consumed either (1) a HF breakfast, (2) a LF breakfast isoenergetic to HF (LFE) or (3) a LF breakfast of equal mass to HF (LFM). Gastric emptying half time measured using the sodium [ 13 C] acetate breath test was delayed after HF compared to LF meals (HF: 102 Æ 11, LFE: 96 Æ 13, LFM: 95 Æ 13 min, mean Æ SD). Fullness increased and desire to eat decreased following the LFE breakfast measured using visual analogue scales. Eating a HF breakfast increased the energy, fat and protein from an ad libitum buffet meal given 4 h after lunch. In conclusion, eating a HF breakfast delayed gastric emptying of lunch and increased food intake 7 h later compared to a LFM breakfast. These data suggest both mass and energy content of food regulate subsequent appetite and feeding and demonstrate the hyperphagic effect of a single HF meal. ß 2010 Elsevier Ltd. All rights reserved. * Corresponding author at: Department of PE and Sport Sciences, Faculty of Education and Health Sciences, University of Limerick, Castletroy, Limerick, Ireland. E-mail addresses: mclegg@brookes.ac.uk (M. Clegg), amir.shafat@ul.ie (A. Shafat). G Model APPET-947; No. of Pages 7 Please cite this article in press as: Clegg, M., & Shafat, A. Energy and macronutrient composition of breakfast affect gastric emptying of lunch and subsequent food intake, satiety and satiation. Appetite (2010), doi:10.1016/j.appet.2010.02.005 Contents lists available at ScienceDirect Appetite journal homepage: www.elsevier.com/locate/appet 0195-6663/$ – see front matter ß 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.appet.2010.02.005