Appetite control and energy balance: impact of exercise

Abstract

2Exercise is widely regarded as one of the most valuable components of behaviour that can influence body weight and therefore help in the prevention and management of obesity. Indeed long term controlled trials show a clear dose related effect of exercise on body weight. However, there is a suspicion, particularly fuelled by media reports, that exercise serves to increase hunger and drive up food intake thereby nullifying the energy expended through activity. Not everyone performing regular exercise will lose weight, and several investigations have demonstrated a huge individual variability in the response to exercise regimes. What accounts for this heterogeneous response? First, exercise (or physical activity) through the expenditure of energy will influence the energy balance equation with the potential to generate an energy deficit. However, energy expenditure also influences the control of appetite (i.e. the physiological and psychological regulatory processes underpinning feeding) and energy intake. This dynamic interaction means that the prediction of a resultant shift in energy balance, and therefore weight change, will be complicated. In changing EI, exercise will impact on the biological mechanisms controlling appetite. It is becoming recognized that the major influences on the expression of appetite arise from fat-free mass and fat mass, Resting Metabolic Rate, gastric adjustment to ingested food, changes in episodic peptides including insulin, ghrelin, CCK, GLP-1 and PYY, as well as tonic peptides such as leptin. Moreover there is evidence that exercise will influence all of these components which, in turn, influence the drive to eat through the modulation of hunger (a conscious sensation reflecting a mental urge to eat) and adjustments in post-prandial satiety via an interaction with food composition. The specific actions of exercise on each physiological component will vary in strength from person to person (according to individual physiological characteristics) and with the intensity and duration of exercise. Therefore, individual responses to exercise will be highly variable and difficult to predict. Background Issues

Acute post-exercise energy and macronutrient intake in lean and obese youth: a systematic review and meta-analysis

“…The effect of acute exercise on energy intake has been widely explored and discussed in adults for the last 20 years (3,5,6). Recently, the interest around this question in pediatric population emerged (10).…”

Fysisk aktivitet og vektreduksjon

“…Overvekt er rangert som den fjerde største risikofaktoren for den globale sykdomsbyrden (1), mens den i Norge har ligget på tredjeplass (2). Det er en viss enighet om kostens betydning for overvekt (3,4), mens betydningen av fysisk aktivitet derimot er mer omdiskutert (5,6).…”

“…etter en treningsøkt, vil trolig høyere fysisk aktivitetsnivå på-virke appetittreguleringen ved at man blir raskere mett ved påfølgende måltid, grunnet økt følsomhet for sentrale hormoner som leptin og insulin. Det resulterer dermed ikke nødvendigvis i høyere energiinntak (5,6).…”

“…På den ene siden kan endret kroppssammensetning, i form av mindre fettmasse og større andel fettfri masse, gi høyere hvilestoffskifte og høyere totalt energiforbruk, noe som kan gi økt energiinntak (5). På den andre siden kan mindre fettmasse og mer fettfri masse også gi økt insulinsensitivitet og bedre apetittregulering, og dermed ikke nødvendigvis et høyere energiinntak (5).…”

Acute and Chronic Effects of Exercise on Appetite, Energy Intake and Appetite-Related Hormones: the Modulating Effect of Adiposity, Sex and Habitual Physical Activity

“…In spite of the influence of purposeful exercise on appetite, appetite-related hormones and food intake, varying amounts of habitual physical activity may modify appetitive responses [18]. Evidence from cross-sectional research has indicated that inactive individuals have impaired energy intake regulation which may facilitate a positive energy balance and consequential weight gain [10,98]. This section will discuss recent research that has explored differences in appetite-related responses to exercise interventions between habitually active verses inactive individuals.…”