Nutrition: Macronutrient metabolism

2020 ◽  
pp. 1839-1854
Author(s):  
Keith N. Frayn ◽  
Rhys D. Evans
Keyword(s):  
Amino Acids ◽  
Food Intake ◽  
Energy Expenditure ◽  
Complex Systems ◽  
Metabolic Control ◽  
Energy Intake ◽  
Energy Supply ◽  
The Body ◽  
Daily Lives ◽  
Storage Pools

Food intake is sporadic and, in many cultures, occurs in three daily boluses. At the same time, energy expenditure is continuous and can vary to a large extent independently of the pattern of energy intake, although fixed or predictable demands (e.g. through occupation) means that in most persons food intake and energy expenditure are soon balanced. The body has developed complex systems that direct excess nutrients into storage pools; as they are needed, they also regulate the mobilization of nutrients from these pools. Carbohydrate, lipid, and protein (the latter a source of amino acids) are the three types of energy supply that are stored variably and assimilated from food each day. That we can carry on our daily lives without thinking about whether to store or mobilize fuels, and which to use, attests to the remarkable efficiency and refinement of these systems of metabolic control.

Nutrition: macronutrient metabolism

2010 ◽  
pp. 1479-1486
Author(s):  
Keith N. Frayn
Keyword(s):  
Amino Acids ◽  
Food Intake ◽  
Energy Expenditure ◽  
Complex Systems ◽  
The Body ◽  
Fuel Tank ◽  
Fuel Oxidation ◽  
Daily Lives ◽  
Major Nutrients ◽  
Storage Pools

Food intake is sporadic: for most people it occurs in three major boluses each day. Energy expenditure, however, is continuous, with variations during the day that bear no resemblance to the pattern of energy intake, except that over some reasonable period of time (a week or more) the two will, in most people, match almost exactly. Therefore the body has developed complex systems that direct nutrients into storage pools when they are in excess, and that regulate the mobilization of nutrients from these pools as they are needed. The situation is analogous to the fuel tank of a car and the throttle that regulates fuel oxidation, except that in the car there is just one fuel and just one engine: in humans there are three major nutrients and a variety of tissues and organs, each of which may have its own preferences for fuels, that vary with time. Carbohydrate, fat, and protein (made up of amino acids), are the three sources of energy which are variably stored and assimilated from food each day. The fact that we can carry on our daily lives without thinking about whether to store or mobilize fuels, and which to use, attests to the remarkable efficiency of these control systems....

scholarly journals Severe protein deficiency induces hepatic expression and systemic level of FGF21 but inhibits its hypothalamic expression in growing rats

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Joanna Moro ◽  
Catherine Chaumontet ◽  
Patrick C. Even ◽  
Anne Blais ◽  
Julien Piedcoq ◽  
...  
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Energy Expenditure ◽  
Energy Intake ◽  
Dietary Protein ◽  
Protein Deficiency ◽  
Protein Diet ◽  
Growing Rats ◽  
Low Protein ◽  
Protein Diets

AbstractTo study, in young growing rats, the consequences of different levels of dietary protein deficiency on food intake, body weight, body composition, and energy balance and to assess the role of FGF21 in the adaptation to a low protein diet. Thirty-six weanling rats were fed diets containing 3%, 5%, 8%, 12%, 15% and 20% protein for three weeks. Body weight, food intake, energy expenditure and metabolic parameters were followed throughout this period. The very low-protein diets (3% and 5%) induced a large decrease in body weight gain and an increase in energy intake relative to body mass. No gain in fat mass was observed because energy expenditure increased in proportion to energy intake. As expected, Fgf21 expression in the liver and plasma FGF21 increased with low-protein diets, but Fgf21 expression in the hypothalamus decreased. Under low protein diets (3% and 5%), the increase in liver Fgf21 and the decrease of Fgf21 in the hypothalamus induced an increase in energy expenditure and the decrease in the satiety signal responsible for hyperphagia. Our results highlight that when dietary protein decreases below 8%, the liver detects the low protein diet and responds by activating synthesis and secretion of FGF21 in order to activate an endocrine signal that induces metabolic adaptation. The hypothalamus, in comparison, responds to protein deficiency when dietary protein decreases below 5%.

scholarly journals What processes are involved in the appetite response to moderate increases in exercise-induced energy expenditure?

1999 ◽  
Vol 58 (1) ◽  
pp. 107-113 ◽  
Author(s):  
Neil A. King
Keyword(s):  
Food Intake ◽  
Energy Expenditure ◽  
Energy Intake ◽  
Weak Coupling ◽  
Eating Behaviour ◽  
Tight Coupling ◽  
Living Situation ◽  
Energy Value ◽  
Exercise Induced ◽  
Response To Exercise

It is intuitive that an energy deficit induced by exercise induces an automatic increased drive for food (hunger and energy intake). However, the absence of a compensatory increase in energy intake (EI) in response to an exercise-induced increase in energy expenditure (EE) is now well documented. Thus, there is a weak coupling between exercise-induced increases in EE and EI. One paradox related to the phenomenon of a weak coupling between the exercise-induced EE and EI is the observation of a positive relationship between physical activity and food intake in the long-term free-living situation (i.e. tight coupling between EE and EI). It is possible, therefore, that a period of transition (uncoupling) occurs in the short-term, before a steady-state (coupling) condition is achieved. It is likely that a combination of physiological and behavioural adaptations occur in order to achieve a tight coupling between EE and EI. The precise physiological and behavioural changes that take place to obtain a new equilibrium (i.e. coupling between EE and EI) are still undetermined. The expectation that exercise-induced increases in EE should drive up hunger and food intake tends to be based on the concept of a strong coupling between physiology and behaviour. However, because of the individual's strong volitional control over eating behaviour, the psychological influences on the appetite response to exercise should not be undervalued. The psychological position of the individual (e.g. dietary restraint, food-related cognitions, reasons for exercising) could have a very strong influence on the food intake response to exercise. Misjudgements concerning the energy value of the food (EI) relative to the energy value of the exercise (EE) could be one possibility why exercise fails to be a successful method of weight loss for some individuals.

scholarly journals Endocrine factors in the hypothalamic regulation of food intake in females: a review of the physiological roles and interactions of ghrelin, leptin, thyroid hormones, oestrogen and insulin

2011 ◽  
Vol 24 (1) ◽  
pp. 132-154 ◽  
Author(s):  
V. Somogyi ◽  
A. Gyorffy ◽  
T. J. Scalise ◽  
D. S. Kiss ◽  
G. Goszleth ◽  
...  
Keyword(s):  
Food Intake ◽  
Energy Expenditure ◽  
Thyroid Hormones ◽  
Energy Homeostasis ◽  
The Body ◽  
Feedback Information ◽  
Hypothalamic Regulation ◽  
The Individual ◽  
Desire To Eat ◽  
The Brain

Controlling energy homeostasis involves modulating the desire to eat and regulating energy expenditure. The controlling machinery includes a complex interplay of hormones secreted at various peripheral endocrine endpoints, such as the gastrointestinal tract, the adipose tissue, thyroid gland and thyroid hormone-exporting organs, the ovary and the pancreas, and, last but not least, the brain itself. The peripheral hormones that are the focus of the present review (ghrelin, leptin, thyroid hormones, oestrogen and insulin) play integrated regulatory roles in and provide feedback information on the nutritional and energetic status of the body. As peripheral signals, these hormones modulate central pathways in the brain, including the hypothalamus, to influence food intake, energy expenditure and to maintain energy homeostasis. Since the growth of the literature on the role of various hormones in the regulation of energy homeostasis shows a remarkable and dynamic expansion, it is now becoming increasingly difficult to understand the individual and interactive roles of hormonal mechanisms in their true complexity. Therefore, our goal is to review, in the context of general physiology, the roles of the five best-known peripheral trophic hormones (ghrelin, leptin, thyroid hormones, oestrogen and insulin, respectively) and discuss their interactions in the hypothalamic regulation of food intake.

Leptin effect in ob/ob mice under thermoneutral conditions depends not necessarily on central satiation

2000 ◽  
Vol 278 (3) ◽  
pp. R790-R795 ◽  
Author(s):  
Johannes Rafael ◽  
Andreas W. Herling
Keyword(s):  
Body Composition ◽  
Adipose Tissue ◽  
Food Intake ◽  
Energy Expenditure ◽  
Energy Supply ◽  
Traditional View ◽  
Food Energy ◽  
Maximal Energy ◽  
Endogenous Lipid

Energy expenditure in ob/ob mice kept at thermoneutrality was quantified from food intake and body composition of mice treated with leptin over 15 and 75 days, respectively. Energy expenditure in response to 15 days of treatment with leptin was twice as high as under pair-feeding conditions, indicating extensive breakdown of adipose tissue independent of a centrally mediated satiation. Leptin-induced reduction of food intake ceased during treatment with leptin over 75 days, when the lipid reserves of the mice were depleted and energy expenditure became similar to that in lean mice. Energy mobilized in leptin-treated ob/ob mice from endogenous lipid resources and similar to the food energy consumed in hyperphagic ob/ob controls may cause satiation. Maximal energy expenditure in both groups may correspond to their energy supply: energy expenditure in ob/ob mice was shown to be correlated to the food intake in the absence of leptin. Leptin effects observed in ob/ob mice under thermoneutral conditions may modify the traditional view of the functionality of the hormone.

scholarly journals The Impact of Time of Day on Energy Expenditure: Implications for Long-Term Energy Balance

Nutrients ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2383 ◽  
Author(s):  
Shaw ◽  
Leung ◽  
Jong ◽  
Coates ◽  
Davis ◽  
...  
Keyword(s):  
Energy Balance ◽  
Energy Expenditure ◽  
Energy Intake ◽  
Experimental Studies ◽  
Time Of Day ◽  
Circadian System ◽  
The Body ◽  
Energy Regulation ◽  
Meal Timing ◽  
The Impact

There is evidence to indicate that the central biological clock (i.e., our endogenous circadian system) plays a role in physiological processes in the body that impact energy regulation and metabolism. Cross-sectional data suggest that energy consumption later in the day and during the night is associated with weight gain. These findings have led to speculation that when, as well as what, we eat may be important for maintaining energy balance. Emerging literature suggests that prioritising energy intake to earlier during the day may help with body weight maintenance. Evidence from tightly controlled acute experimental studies indicates a disparity in the body’s ability to utilise (expend) energy equally across the day and night. Energy expenditure both at rest (resting metabolic rate) and after eating (thermic effect of food) is typically more efficient earlier during the day. In this review, we discuss the key evidence for a circadian pattern in energy utilisation and balance, which depends on meal timing. Whilst there is limited evidence that simply prioritising energy intake to earlier in the day is an effective strategy for weight loss, we highlight the potential benefits of considering the role of meal timing for improving metabolic health and energy balance. This review demonstrates that to advance our understanding of the contribution of the endogenous circadian system toward energy balance, targeted studies that utilise appropriate methodologies are required that focus on meal timing and frequency.

scholarly journals Validation of the Danish 7-day pre-coded food diary among adults: energy intake v. energy expenditure and recording length

2009 ◽  
Vol 102 (12) ◽  
pp. 1838-1846 ◽  
Author(s):  
Anja Biltoft-Jensen ◽  
Jeppe Matthiessen ◽  
Lone B. Rasmussen ◽  
Sisse Fagt ◽  
Margit V. Groth ◽  
...  
Keyword(s):  
Food Intake ◽  
Energy Expenditure ◽  
Energy Intake ◽  
Group Level ◽  
Food Diary ◽  
Dietary Survey ◽  
Limits Of Agreement ◽  
Free Living ◽  
Food Items ◽  
In The Beginning

Under-reporting of energy intake (EI) is a well-known problem when measuring dietary intake in free-living populations. The present study aimed at quantifying misreporting by comparing EI estimated from the Danish pre-coded food diary against energy expenditure (EE) measured with a validated position-and-motion instrument (ActiReg®). Further, the influence of recording length on EI:BMR, percentage consumers, the number of meal occasions and recorded food items per meal was examined. A total of 138 Danish volunteers aged 20–59 years wore the ActiReg® and recorded their food intake for 7 consecutive days. Data for 2504 participants from the National Dietary Survey 2000–2 were used for comparison of characteristics and recording length. The results showed that EI was underestimated by 12 % on average compared with EE measured by ActiReg® (PreMed AS, Oslo, Norway). The 95 % limits of agreement for EI and EE were − 6·29 and 3·09 MJ/d. Of the participants, 73 % were classified as acceptable reporters, 26 % as under-reporters and 1 % as over-reporters. EI:BMR was significantly lower on 1–3 consecutive recording days compared with 4–7 recording days (P < 0·03). Percentage consumers of selected food items increased with number of recording days. When recording length was 7 d, the number of reported food items per meal differed between acceptable reporters and under-reporters. EI:BMR was the same on 4 and 7 consecutive recording days. This was, however, a result of under-reporting in the beginning and the end of the 7 d reporting. Together, the results indicate that EI was underestimated at group level and that a 7 d recording is preferable to a 4 d recording period.

scholarly journals Kappa-Carrageenan Inhibited the High-Fat-Diet-Induced Obesity Through Up-Regulating the Hepatic Sirt1 Gene Expression

2021 ◽  
Vol 5 (Supplement_2) ◽  
pp. 503-503
Author(s):  
Zhiji Huang ◽  
Yafang Ma ◽  
Chunbao Li
Keyword(s):  
Gene Expression ◽  
Weight Gain ◽  
Energy Expenditure ◽  
Energy Intake ◽  
High Fat Diet ◽  
The Body ◽  
High Fat ◽  
Diet Induced Obesity ◽  
Sirt1 Gene ◽  
Kappa Carrageenan

Abstract Objectives Kappa-Carrageenan(CGN) is a widely used food additive in the meat industry and a highly viscous soluble dietary fiber which can hardly be fermented. It has been shown to be able to regulate the energy metabolism and inhibit diet-induced obesity. However, the mechanism is not well understood. The purpose of this study is to investigate the mechanisms of κ-carrageenan to inhibit the body weight gain. Methods A high-fat diet incorporated with lard, pork protein and CGN (2% or 4%, w/w) was given to C57BL/6J mice for 90 days. The energy intake and weight changes were measured every three days. After the dietary intervention, mice were sacrificed, liver and epididymal adipose tissues were taken for real-time polymerase chain reaction (RT-qPCR) analysis. Results The CGN in the high-fat diet restricted weight gain by decreasing liver and adipose mass without inhibiting energy intake.  The genes involving energy expenditure such as Acox1, Acadl, CPT-1A and Sirt1 were upregulated in the mice fed with carrageenan. However, the genes responsible for lipid synthesis were not significantly different compared to the diet-induced obese model. Conclusions The anti-obesity effect of the CGN in high-fat diet could be highly related to the enhancement of energy expenditure through up-regulating the downstream genes which promote β-oxidation by increasing the Sirt1 gene expression in liver. Funding Sources Ministry of Science and Technology of the People's Republic of China (10000 Talent Project)

scholarly journals Cold-induced hyperphagia requires AgRP-neuron activation in mice

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Jennifer Deem ◽  
Chelsea L Faber ◽  
Christian Pedersen ◽  
Bao Anh Phan ◽  
Sarah A Larsen ◽  
...  
Keyword(s):  
Food Intake ◽  
Energy Expenditure ◽  
Energy Intake ◽  
Cold Exposure ◽  
Energy Homeostasis ◽  
Cold Environment ◽  
Energy Demands ◽  
Acute Cold Exposure ◽  
Neuron Activation ◽  
Increase Food Intake

To maintain energy homeostasis during cold exposure, the increased energy demands of thermogenesis must be counterbalanced by increased energy intake. To investigate the neurobiological mechanisms underlying this cold-induced hyperphagia, we asked whether agouti-related peptide (AgRP) neurons are activated when animals are placed in a cold environment and, if so, whether this response is required for the associated hyperphagia. We report that AgRP-neuron activation occurs rapidly upon acute cold exposure, as do increases of both energy expenditure and energy intake, suggesting the mere perception of cold is sufficient to engage each of these responses. We further report that silencing of AgRP neurons selectively blocks the effect of cold exposure to increase food intake but has no effect on energy expenditure. Together, these findings establish a physiologically important role for AgRP neurons in the hyperphagic response to cold exposure.

scholarly journals Central and peripheral control of food intake

2017 ◽  
Vol 51 (1) ◽  
pp. 52-70 ◽  
Author(s):  
M. M. I. Abdalla
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Energy Expenditure ◽  
Current Knowledge ◽  
The Body ◽  
Therapeutic Implications ◽  
New Therapeutic Approaches ◽  
Control Food ◽  
Adiposity Signals ◽  
Control Food Intake

Abstract The maintenance of the body weight at a stable level is a major determinant in keeping the higher animals and mammals survive. Th e body weight depends on the balance between the energy intake and energy expenditure. Increased food intake over the energy expenditure of prolonged time period results in an obesity. Th e obesity has become an important worldwide health problem, even at low levels. The obesity has an evil effect on the health and is associated with a shorter life expectancy. A complex of central and peripheral physiological signals is involved in the control of the food intake. Centrally, the food intake is controlled by the hypothalamus, the brainstem, and endocannabinoids and peripherally by the satiety and adiposity signals. Comprehension of the signals that control food intake and energy balance may open a new therapeutic approaches directed against the obesity and its associated complications, as is the insulin resistance and others. In conclusion, the present review summarizes the current knowledge about the complex system of the peripheral and central regulatory mechanisms of food intake and their potential therapeutic implications in the treatment of obesity.

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