Laurent Brondel

Acute partial sleep deprivation increases food intake in healthy men

BACKGROUND Acute partial sleep deprivation increases plasma concentrations of ghrelin and decreases those of leptin. OBJECTIVE The objective was to observe modifications in energy intake and physical activity after acute partial sleep deprivation in healthy men. DESIGN Twelve men [age: 22 +/- 3 y; body mass index (in kg/m(2)): 22.30 +/- 1.83] completed a randomized 2-condition crossover study. During the first night of each 48-h session, subjects had either approximately 8 h (from midnight to 0800) or approximately 4 h (from 0200 to 0600) of sleep. All foods consumed subsequently (jam on buttered toast for breakfast, buffet for lunch, and a free menu for dinner) were eaten ad libitum. Physical activity was recorded by an actimeter. Feelings of hunger, perceived pleasantness of the foods, desire to eat some foods, and sensation of sleepiness were also evaluated. RESULTS In comparison with the 8-h sleep session, subjects consumed 559 +/- 617 kcal (ie, 22%) more energy on the day after sleep restriction (P < 0.01), and preprandial hunger was higher before breakfast (P < 0.001) and dinner (P < 0.05). No change in the perceived pleasantness of the foods or in the desire to eat the foods was observed. Physical activity from 1215 to 2015 was higher after sleep restriction than after 8 h of sleep (P < 0.01), even though the sensation of sleepiness was more marked (P < 0.01). CONCLUSIONS One night of reduced sleep subsequently increased food intake and, to a lesser extent, estimated physical activity-related energy expenditure in healthy men. These experimental results, if confirmed by long-term energy balance measurements, suggest that sleep restriction could be a factor that promotes obesity. This trial was registered at clinicaltrials.gov as NCT00986492.

Lipid oxidation in overweight men after exercise and food intake

Fat oxidation (FO) is optimized during low- to moderate-intensity exercise in lean and obese subjects, whereas high-intensity exercise induces preferential FO during the recovery period. After food intake during the postexercise period, it is unknown if FO differs according to the intensity exercise in overweight subjects. Fat oxidation was thus evaluated in overweight men after low- and high-intensity exercise during the recovery period before and after food intake as well as during a control session. Ten healthy, sedentary, overweight men (age, 27.9 +/- 5.6 years; body mass index, 27.8 +/- 1.3 kg m(-2); maximal oxygen consumption, 37 +/- 3.9 mL min(-1) kg(-1)) exercised on a cycloergometer (energy expenditure = 300 kcal) at 35% (E35) or 70% (E70) maximal oxygen consumption or rested (Cont). The subjects were fed 30 minutes after the exercise with 300 kcal (1256 kJ) more energy in the exercise sessions than in the Cont session. Respiratory quotient and FO were calculated by indirect calorimetry. Blood samples were analyzed to measure plasma glycerol, nonesterified fatty acid, glucose, and insulin. During exercise, mean respiratory quotient was lower (P < .05) and FO was higher (P < .01) in the E35 than in the E70 session (FO [in mg min(-1)]: E35 = 290 +/- 12, E70 = 256 +/- 38, and Cont = 131 +/- 7). Conversely, FO was higher in the E70 than in both the E35 session and the Cont session during the immediate recovery as well as during the postprandial recovery period (P = .005 for all; FO from the end of the exercise to the end of the session [in grams]: E70 = 45.7 +/- 8.9, E35 = 38.2 +/- 6.8, and Cont = 36.0 +/- 4.3). Blood parameters did not differ between the 3 sessions but changed according to the absorption of the nutrients. In overweight subjects, high-intensity exercise increased FO during the postexercise period even after food intake compared with the low-intensity exercise and the control session.

Monotonous consumption of fibre-enriched bread at breakfast increases satiety and influences subsequent food intake.

This study aimed to observe the influence of the monotonous consumption of two types of fibre-enriched bread at breakfast on hedonic liking for the bread, subsequent hunger and energy intake. Two groups of unrestrained normal weight participants were given either white sandwich bread (WS) or multigrain sandwich bread (MG) at breakfast (the sensory properties of the WS were more similar to the usual bread eaten by the participants than those of the MG). In each group, two 15-day cross-over conditions were set up. During the experimental condition the usual breakfast of each participant was replaced by an isocaloric portion of plain bread (WS or MG). During the control condition, participants consumed only 10 g of the corresponding bread and completed their breakfast with other foods they wanted. The results showed that bread appreciation did not change over exposure even in the experimental condition. Hunger was lower in the experimental condition than in the control condition. The consumption of WS decreased energy intake while the consumption of MG did not in the experimental condition compared to the corresponding control one. In conclusion, a monotonous breakfast composed solely of a fibre-enriched bread may decrease subsequent hunger and, when similar to a familiar bread, food intake.

Substrate oxidation influences liking, wanting, macronutrient selection, and consumption of food in humans–

BACKGROUND Several carbohydrate-based models of feeding have been described. The influence of the substrate oxidation rate on liking, wanting, and macronutrient selection, however, is not known in humans. OBJECTIVE The aim of this study was to investigate the influence of the substrate oxidation rate on the above variables. DESIGN A randomized 4-condition study was conducted in 16 normal-weight men (mean ± SD age: 23 ± 3 y). The sessions differed in the composition of breakfast, which was either high in carbohydrates (HC) or low in carbohydrates (LC) or high in fat (HF) or low in fat (LF). Two hours and 20 minutes after breakfast, energy expenditure (EE) and respiratory exchange ratios (RERs) were measured. Next, olfactory liking for 4 foods (sweet and fatty) and ad libitum energy intake (carbohydrate- and fat-rich bread) were evaluated. RESULTS EE was higher (P < 0.001) and subsequent intake was lower (P < 0.01) after the HC and HF breakfasts than after the LC and LF breakfasts. The HC and LC breakfasts induced a higher RER (P < 0.001), lower olfactory liking for sweet foods (P < 0.05), and the consumption of a lower proportion of carbohydrate-rich bread (P< 0.05) than did the HF and LF breakfasts. The HF breakfast induced the lowest RER (P < 0.001), the lowest olfactory liking for fatty foods (P < 0.05), and the lowest proportion of fat-rich bread consumed (P < 0.01). Above all, a negative correlation was found between the RER and olfactory liking for sweet foods (P < 0.001). CONCLUSION A high fat oxidation rate induces a strong liking for carbohydrates and a low liking for fats, which lends new support to the carbohydrate-based model of feeding. This trial is registered at clinicaltrials.gov as NCT01122082.

Impact of energy density on liking for sweet beverages and caloric-adjustment conditioning in children

BACKGROUND The contribution of sweet beverages to weight gain in children is controversial; the impact of these beverages on caloric adjustment needs clarification. OBJECTIVE We studied the influence of energy-density (ED) conditioning on the liking for sweet beverages and caloric adjustment after their consumption in children. DESIGN We used a within-subject design. Forty-four 8-11-y-old children were exposed to the following 2 distinctly flavored, sweetened beverages: a high-energy (HE) version (150 kcal) and a no-energy (NE) version (0 kcal). During a 4-wk initial conditioning period, children were exposed either 2 or 7 times to each beverage. After a 3-wk stability period (without exposure), children were exposed 3 times to both beverages with a reversed association between the ED and flavor (4-wk reversed-conditioning period). Flavor liking and food intake during meals after the consumption of each beverage were assessed before and after each period. RESULTS After the initial conditioning, the liking for both beverages increased (P < 0.001). After the stability period, the liking for the HE flavor was higher than for the NE flavor (P = 0.024). After the reversed conditioning, the liking for the flavor initially paired with the HE beverage tended to remain higher than for the NE flavor (P = 0.089). Initially, energy intakes during the meal did not differ after the consumption of NE or HE beverages. After the initial conditioning and up until the end of the reversed conditioning, energy intakes were lower after the HE beverage than after the NE beverage regardless of the beverage flavor (eg, after reversal; caloric compensation score: 29%). The number of exposures did not influence liking or energy intake. CONCLUSION After the association between a flavor and ED and reversal of this association, liking may be first guided by ED and then the flavor firstly associated with ED, whereas the partial caloric compensation may consistently be guided by ED. This trial was registered at clinicaltrials.gov as NCT02070185.

Sensory-specific satiety for a food is unaffected by the ad libitum intake of other foods during a meal. Is SSS subject to dishabituation?

Sensory-specific satiety (SSS) is defined as a decrease in the pleasantness of a specific food that has just been eaten to satiation, while other non-eaten foods remain pleasant. The objectives of this study were the following: (1) to investigate whether SSS for a food is affected by the ad libitum intake of other foods presented sequentially during a meal, (2) to compare the development of SSS when foods are presented simultaneously or sequentially during a meal, and (3) to examine whether SSS is modified when foods are presented in an unusual order within a meal. Twelve participants participated in three tasting sessions. In session A, SSS for protein-, fat- and carbohydrate-rich sandwiches was measured after the ad libitum consumption of single type of each of these foods. In session B, SSS was measured for the same three foods consumed ad libitum but presented simultaneously. Session C was identical to session A, except that the presentation order of the three foods was reversed. The results indicate that once SSS for a given food is reached, the ad libitum consumption of other foods with different sensory characteristics does not decrease SSS, regardless of the order in which the foods are presented. Once reached, SSS is thus not subject to dishabituation during a meal.

Influence of substrate oxidation on the reward system, no role of dietary fibre.

It has been suggested that a high intake of dietary fibre helps regulate energy intake and satiety. The present study aimed to examine whether dietary fibre influenced the liking and wanting components of the food reward system, the metabolic state or subsequent intake. Five sessions involving 32 normal-weight subjects (16 men and 16 women, 30.6 ± 7.6 year) were held. The sessions differed in the composition of the bread eaten during breakfasts (dietary fibre content varied from 2.4 to 12.8 g/100 g). Several factors such as the palatability, weight, volume, energy content and macronutrient composition of the breakfasts were adjusted. Energy expenditure, the respiratory quotient (R), olfactory liking for four foods, wanting for six other foods, and hunger sensations were evaluated before and after the breakfast, as well as before a morning snack. The results showed no significant differences after ingestion of the various breads. Interestingly, R correlated with olfactory liking and with wanting, which highlights in an original manner the influence of the metabolic state on hedonic sensations for food. In conclusion, dietary fibre was found to have no effect on olfactory liking and wanting, and had no detectable effect on satiety sensations or on subsequent energy intake.

Taste disorders in disease

Among the different sensory systems, gustation is one of the most elaborate. In its sensory task, gustation is helped by interactions with other sensory systems (olfaction, vision, audition, and somatosensory, trigeminal and thermal sensations). It allows the detection and identification of soluble compounds which can be ingested or must be avoided. This function is fundamental to ingestive behavior (energy intake and selection of nutrients) in order to meet physiological needs. Taste is also fundamental to the genesis of hedonic sensations and, therefore, the desire to eat (appetite). The tasting step is also the first stage of the digestion, absorption, and storage of nutrients due to anticipatory reflexes. Taste disorders are, therefore, not simple hedonic alterations of the epicurean canon of gastronomy; taste disorders can worsen and even compromise vital functions (malnutrition and aggravation of an underlying disease), and they always reduce quality of life. Many drugs and numerous diseases can cause gustatory loss. The mechanisms leading to taste alteration are varied. In medical practice, taste problems are frequent but not diagnosed often enough, in particular in metabolic syndrome and obesity, in neurodegenerative diseases, and in cancer. Increasing knowledge of taste disorders in disease could improve our understanding of taste pathophysiology, and the prevention of malnutrition by diets adapted to taste impairment.

Mechanisms involved in the control of feeding behavior in relation to food flavor

Abstract Intake is one of the most essential behaviors since all living organisms require adequate nutrients for survival. Ingestive behavior is a complex phenomenon under the influence of three main mechanisms: homeostatic, hedonic, and cognitive. The sensory perception resulting from the taste, odor, texture, and temperature of the food, that is, its flavor, allow us to analyze, identify and eventually recognize the food and will then be a central contributor in the decision to ingest or reject the food. The treatment of sensory information (perception) is a complex multimodal process. Food seeking and ingestion are also influenced by (1) memories of the orosensory, olfactory and postingestive effects of previous encounters with a similar substance; and (2) emotional, cognitive and social factors such as culture and context. This aim of this chapter is to describe some of these mechanisms as well as their time course through the alimentary sequences.

Dynamics of Aroma Release during Cheese Consumption: Influence of the Physiological State

The influence of satiation before and after a pasta meal was studied through the evaluation of aroma release and chewing activity during the consumption of a flavored model cheese. Aroma release during cheese consumption was found to be higher after satiation than before. The difference can be explained by an increase in the duration of the chewing sequence and an increase in the chewing muscular work after satiation. However, the pulmonary flow was not affected by satiation.