Food after deprivation rewards the earlier eating

► Intake of the food eaten before deprivation is increased by the later physiological repletion. ► This reward of eating by assimilation of nutrients is stronger when the deprivation is longer. ► Such a simple learning mechanism in animals is likely to operate unconsciously in people. ► This long-delay food reward process may be making an unnoticed contribution to obesity. Food intake can be increased by learning to anticipate the omission of subsequent meals. We present here a new theory that such anticipatory eating depends on an associative process of instrumental reinforcement by the nutritional repletion that occurs when access to food is restored. Our evidence over the last decade from a smooth-brained omnivore has been that food after deprivation rewards intake even when those reinforced ingestive responses occur long before the physiological signals from renewed assimilation. Effects of food consumed after self-deprivation might therefore reward extra eating in human beings, through brain mechanisms that could operate outside awareness. That would have implications for efforts to reduce body weight. This food reward mechanism could be contributing to the failure of the dietary component of interventions on obesity within controlled trials of the management or prevention of disorders such as hypertension, atherosclerosis and type 2 diabetes.