scholarly journals Physical Activity: An Important Adaptative Mechanism for Body-Weight Control

ISRN Obesity ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Carmine Finelli ◽  
Saverio Gioia ◽  
Nicolina La Sala

We review the current concepts about energy expenditure and evaluate the physical activity (PhA) in the context of this knowledge and the available literature. Regular PhA is correlated with low body weight and low body fat mass. The negative fat balance is probably secondary to this negative energy balance. Nonexercise activity thermogenesis (NEAT) and physical activity, that is crucial for weight control, may be important in the physiology of weight change. An intriguing doubt that remains unresolved is whether changes in nutrient intake or body composition secondarily affect the spontaneous physical activity.

2003 ◽  
Vol 62 (3) ◽  
pp. 663-666 ◽  
Author(s):  
L. Tappy ◽  
C. Binnert ◽  
Ph. Schneiter

Regular physical exercise and endurance training are associated with low body weight and low body fat mass. The relationship between exercise and body-weight control is complex and incompletely understood. Regular exercise may decrease energy balance through an increase in energy expenditure or an increase in fat oxidation. It may also contribute to weight loss by modulating nutrient intake. An intriguing question that remains unresolved is whether changes in nutrient intake or body composition secondarily affect spontaneous physical activity. If this were the case, physical activity would represent a major adaptative mechanism for body-weight control.


1995 ◽  
Vol 73 (3) ◽  
pp. 337-347 ◽  
Author(s):  
Klaas R. Westerterp ◽  
Jeroen H. H. L. M. Donkers ◽  
Elisabeth W. H. M. Fredrix ◽  
Piet oekhoudt

In adults, body mass (BM) and its components fat-free mass (FFM) and fat mass (FM) are normally regulated at a constant level. Changes in FM and FFM are dependent on energy intake (EI) and energy expenditure (EE). The body defends itself against an imbalance between EI and EE by adjusting, within limits, the one to the other. When, at a given EI or EE, energy balance cannot be reached, FM and FFM will change, eventually resulting in an energy balance at a new value. A model is described which simulates changes in FM and FFM using EI and physical activity (PA) as input variables. EI can be set at a chosen value or calculated from dietary intake with a database on the net energy of foods. PA can be set at a chosen multiple of basal metabolic rate (BMR) or calculated from the activity budget with a database on the energy cost of activities in multiples of BMR. BMR is calculated from FFM and FM and, if necessary, FFM is calculated from BM, height, sex and age, using empirical equations. The model uses existing knowledge on the adaptation of energy expenditure (EE) to an imbalance between EI and EE, and to resulting changes in FM and FFM. Mobilization and storage of energy as FM and FFM are functions of the relative size of the deficit (EI/EE) and of the body composition. The model was validated with three recent studies measuring EE at a fixed EI during an interval with energy restriction, overfeeding and exercise training respectively. Discrepancies between observed and simulated changes in energy stores were within the measurement precision of EI, EE and body composition. Thus the consequences of a change in dietary intake or a change in physical activity on body weight and body composition can be simulated.


2010 ◽  
Vol 298 (3) ◽  
pp. E726-E734 ◽  
Author(s):  
Paulo José Forcina Martins ◽  
Marina Soares Marques ◽  
Sergio Tufik ◽  
Vânia D'Almeida

Several pieces of evidence support that sleep duration plays a role in body weight control. Nevertheless, it has been assumed that, after the identification of orexins (hypocretins), the molecular basis of the interaction between sleep and energy homeostasis has been provided. However, no study has verified the relationship between neuropeptide Y (NPY) and orexin changes during hyperphagia induced by sleep deprivation. In the current study we aimed to establish the time course of changes in metabolite, endocrine, and hypothalamic neuropeptide expression of Wistar rats sleep deprived by the platform method for a distinct period (from 24 to 96 h) or sleep restricted for 21 days (SR-21d). Despite changes in the stress hormones, we found no changes in food intake and body weight in the SR-21d group. However, sleep-deprived rats had a 25–35% increase in their food intake from 72 h accompanied by slight weight loss. Such changes were associated with increased hypothalamus mRNA levels of prepro-orexin (PPO) at 24 h followed by NPY at 48 h of sleep deprivation. Conversely, sleep recovery reduced the expression of both PPO and NPY, which rapidly brought the animals to a hypophagic condition. Our data also support that sleep deprivation rapidly increases energy expenditure and therefore leads to a negative energy balance and a reduction in liver glycogen and serum triacylglycerol levels despite the hyperphagia. Interestingly, such changes were associated with increased serum levels of glucagon, corticosterone, and norepinephrine, but no effects on leptin, insulin, or ghrelin were observed. In conclusion, orexin activation accounts for the myriad changes induced by sleep deprivation, especially the hyperphagia induced under stress and a negative energy balance.


2021 ◽  
pp. 155982762198928
Author(s):  
Monica Kazlausky Esquivel

Individuals seeking to achieve weight loss are encouraged to achieve a negative energy balance, essentially eat less and move more. The complex relationship between energy expenditure and intake is often overlooked, leaving individuals and practitioners underwhelmed by the results of weight loss efforts. Independently, physical activity and diet interventions can yield modest weight loss and when combined have synergistic effects that promote sustained weight loss. Although physical activity benefits appetite suppression, reduces food rewards, and can be considered a gateway to healthy eating, high levels of daily activity are needed to induce weight loss. Diet is an important component to achieving weight loss, and high-protein diets have the potential for supporting weight loss as well. This column will be focused on the benefits of physical activity in reducing body weight, more specifically, the interdependent relationship between dietary intake and physical activity in achieving weight reduction.


2003 ◽  
Vol 62 (3) ◽  
pp. 651-661 ◽  
Author(s):  
J. E. Blundell ◽  
R. J. Stubbs ◽  
D. A. Hughes ◽  
S. Whybrow ◽  
N. A. King

Physical activity has the potential to modulate appetite control by improving the sensitivity of the physiological satiety signalling system, by adjusting macronutrient preferences or food choices and by altering the hedonic response to food. There is evidence for all these actions. Concerning the impact of physical activity on energy balance, there exists a belief that physical activity drives up hunger and increases food intake, thereby rendering it futile as a method of weight control. There is, however, no evidence for such an immediate or automatic effect. Short (1–2 d)-term and medium (7–16 d)-term studies demonstrate that men and women can tolerate substantial negative energy balances of ≤4MJ energy cost/d when performing physical activity programmes. Consequently, the immediate effect of taking up exercise is weight loss (although this outcome is sometimes difficult to assess due to changes in body composition or fluid compartmentalization). However, subsequently food intake begins to increase in order to provide compensation for about 30% of the energy expended in activity. This compensation (up to 16 d) is partial and incomplete. Moreover, subjects separate into compensators and non-compensators. The exact nature of these differences in compensation and whether it is actually reflective of non-compliance with protocols is yet to be determined. Some subjects (men and women) performing activity with a cost of ≤4 MJ/d for 14 d, show no change in daily energy intake. Conversely, it can be demonstrated that when active individuals are forced into a sedentary routine food intake does not decrease to a lower level to match the reduced energy expenditure. Consequently, this situation creates a substantial positive energy balance accompanied by weight gain. The next stage is to further characterize the compensators and non-compensators, and to identify the mechanisms (physiological or behavioural) that are responsible for the rate of compensation and its limits.


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