Variation in the fat mass and obesity–associated (FTO) gene has provided the most robust associations with common obesity to date. However, the role of FTO variants in modulating specific components of energy balance is unknown.

Childhood is a critical period in the development of obesity. Eating patterns established early in life track into later life. Therefore, parental approaches to feeding in their general parenting style, feeding styles and specific feeding practices will have a profound impact on how children eat and grow. A systematic research review following PRISMA guidelines was conducted to identify, discuss and integrate recent research investigating the relationship between parenting styles, feeding styles, feeding practices and body mass index (BMI) in children. Medline (Ovid), PsycINFO, Web of Science and Food Science and Technology Abstracts were systematically searched using sensitive search strategies. Studies were limited to papers published in English between 2010 and February 2015 with participants aged 4 to 12 years old with outcomes including obesity, change in weight, or BMI. The search yielded 31 relevant quantitative peer-reviewed papers meeting all inclusion criteria: 7 longitudinal, 23 cross-sectional, 1 randomised control trial.. Associations between parenting style and child BMI were strongest and most consistent within the longitudinal studies. Uninvolved, indulgent or highly protective parenting was associated with higher child BMI, whereas authoritative parenting was associated with a healthy BMI. Similarly for feeding styles, indulgent feeding was consistently associated with risk of obesity within cross-sectional studies. Specific feeding practices such as restriction and pressure to eat were linked to BMI, especially within cross-sectional studies. Where child traits were measured, the feeding practice appeared to be responsive to the child, therefore restriction was applied to children with a high BMI and pressure to eat applied to children with a lower BMI. Behaviours and styles that are specific to the feeding context are consistently associated with child BMI. However, since obesity emerges over time, it is through longitudinal, carefully measured (through questionnaire and observation) studies which take account of child appetite and temperament that the association between parenting style, feeding style, specific feeding practices and child obesity will be understood.

The close correspondence between energy intake and expenditure over prolonged time periods, coupled with an apparent protection of the level of body adiposity in the face of perturbations of energy balance, has led to the idea that body fatness is regulated via mechanisms that control intake and energy expenditure. Two models have dominated the discussion of how this regulation might take place. The set point model is rooted in physiology, genetics and molecular biology, and suggests that there is an active feedback mechanism linking adipose tissue (stored energy) to intake and expenditure via a set point, presumably encoded in the brain. This model is consistent with many of the biological aspects of energy balance, but struggles to explain the many significant environmental and social influences on obesity, food intake and physical activity. More importantly, the set point model does not effectively explain the ‘obesity epidemic’ – the large increase in body weight and adiposity of a large proportion of individuals in many countries since the 1980s. An alternative model, called the settling point model, is based on the idea that there is passive feedback between the size of the body stores and aspects of expenditure. This model accommodates many of the social and environmental characteristics of energy balance, but struggles to explain some of the biological and genetic aspects. The shortcomings of these two models reflect their failure to address the gene-by-environment interactions that dominate the regulation of body weight. We discuss two additional models – the general intake model and the dual intervention point model – that address this issue and might offer better ways to understand how body fatness is controlled.

The effects of consuming equicaloric preloads with different macronutrient contents on the development of satiety were investigated. Ten normal-weight, nondieting women fasted overnight and then rated hunger, fullness, and food preferences, and the pleasantness of the taste of food samples before and after five different preloads. The greatest changes in the pleasantness of the taste of the food occurred for the eaten food relative to the uneaten food. Macronutrient content of the preloads did not significantly influence the magnitude of these changes or the pleasantness of foods with similar nutrient contents. Therefore, no evidence of nutrient-specificity was obtained. Nutrient composition had a differential effect on hunger, fullness and food intake. Ratings of hunger decreased and fullness increased following the high starch and high protein preloads to a greater extent than after the high fat, high sucrose and mixed content preloads. When a self-selection meal was offered 2 hours after the preloads energy intake and preference for high carbohydrate and high fat food items were significantly decreased by the high protein and high starch preloads. However, no specific reduction in macronutrient intake was observed. In conclusion, differential effects of the preloads were observed in subjective ratings of hunger, fullness, preferences and subsequent food intake, but there was no indication that satiety was macronutrient-specific.