Automatic food intake detection based on swallowing sounds

This paper presents a novel fully automatic food intake detection methodology, an important step toward objective monitoring of ingestive behavior. The aim of such monitoring is to improve our understanding of eating behaviors associated with obesity and eating disorders. The proposed methodology consists of two stages. First, acoustic detection of swallowing instances based on mel-scale Fourier spectrum features and classification using support vector machines is performed. Principal component analysis and a smoothing algorithm are used to improve swallowing detection accuracy. Second, the frequency of swallowing is used as a predictor for detection of food intake episodes. The proposed methodology was tested on data collected from 12 subjects with various degrees of adiposity. Average accuracies of >80% and >75% were obtained for intra-subject and inter-subject models correspondingly with a temporal resolution of 30 s. Results obtained on 44.1 h of data with a total of 7305 swallows show that detection accuracies are comparable for obese and lean subjects. They also suggest feasibility of food intake detection based on swallowing sounds and potential of the proposed methodology for automatic monitoring of ingestive behavior. Based on a wearable non-invasive acoustic sensor the proposed methodology may potentially be used in free-living conditions.     

Definitions of Night Eating in Adolescent Girls

Objective: To describe the prevalence of night eating in a community cohort of black and white girls, using different definitions of night eating as described in the literature. Research Methods and Procedures: Three‐day food diaries collected as part of the National Growth and Health Study were examined to identify episodes of night eating, which was defined in five different ways: eating >25% of daily caloric intake after the last evening meal, eating >25% of daily caloric intake after 7 pm, eating >50% of daily caloric intake after the last evening meal, eating >50% of daily caloric intake after 7 pm, or eating between 11 pm and 4:59 am. Results: Frequency of night eating varied tremendously depending on how the behavior was defined. For the least restrictive definition (>25% of total intake after last meal), 50% to 70% of girls reported one night eating event; for the most restrictive (>50% of total intake after last meal), only 1.5% of 11‐year‐old girls' diaries and 3.5% of 19‐year‐old girls' diaries contained a night eating event. The frequency of night eating decreased dramatically (typically by a factor of 10) if the inclusion criteria required multiple night eating events in a given week. Discussion: A standard definition of night eating behavior is needed to advance the field. An agreed‐on operationalized definition that includes time of day, amount of calories consumed, and a frequency criterion would enable cross‐study comparisons and encourage the examination of developmental and clinical considerations of night eating behavior.     

Lack of Evidence for a Marked Endogenous Component Determining Food Intake in Humans During Forced Desynchrony

In an attempt to investigate the relative importance of endogenous and exogenous factors in determining food intake, 14 healthy subjects were studied while living in an Isolation Unit (where external time cues were absent) for eighteen 28 h “days” (equal to 21 solar days). The subjects were free to spend their waking time as they chose, and they had a free choice of what they ate and when they ate it. The only restrictions were that no naps were allowed in the “daytime,” that some time was required to perform a variety of tests at regular intervals throughout the 18.67 h waking periods, and that any food preparation had to be performed by the subjects themselves. Core (rectal) temperature and activity were monitored throughout, and the subjects answered a questionnaire on their eating habits at 3 h intervals during the waking periods. The questionnaire investigated reasons for eating or not eating a meal during the previous 3 h and, if a meal had been eaten, its type, the factors influencing that choice, and the subjects’ subjective responses (hunger before, enjoyment during, and satiety after) to it. The results were analyzed (two-way ANOVA) in terms of both the imposed day length (the exogenous component) and the free-running period of the temperature rhythm (the endogenous component). Results indicated that by far the main reason for eating/not eating was hunger/lack of hunger rather than factors such as food availability and time-pressure. There were statistically significant effects of time within the imposed waking periods upon the type of meal eaten—“breakfast” tending to be a snack, “lunch” a small hot meal, and the “evening meal” a large hot meal. Hot meals (whether small or large) were associated with more hunger before the meal, more enjoyment of the meal, and a greater degree of satiety afterward than were cold meals. These effects suggest that the individuals adjusted their eating habits to fit in with the imposed wake times. By contrast, the effect of circadian phase upon food intake, the type of meal eaten, and subjective responses to the meal was much weaker, and either statistically nonsignificant (P > 0.10) or only marginally so (0.10 > P > 0.05). For example, a large hot meal was chosen as readily for an “evening meal,” and subjective responses to it were the same, at whatever circadian phase it was eaten. We conclude that food intake during forced desynchronization is dominated by the waking schedule rather than by circadian influences; some of the implications of these findings when eating habits and the metabolism of food are concerned, particularly in night workers, are considered briefly.     

Relationship of Attitudes Toward Fast Food and Frequency of Fast‐food Intake in Adults

The purpose of the study was to examine the association between attitudes toward fast food and the frequency of fast‐food intake in adults. This study is a cross‐sectional evaluation of random digit‐dial telephone surveys to identify patterns of eating away from home and attitudes toward it. Participants included 530 adults (94% white, 65% women, 70% married, 42% with college educated). Attitudes toward fast food was measured using an 11‐item, 4‐dimensional scale: perceived convenience of fast food (α = 0.56); fast food is fun and social (α = 0.55); fast food perceived as unhealthful (α = 0.45); and dislike toward cooking (α = 0.52). Frequency of fast‐food intake was found to be significantly associated with age (odds ratios (OR) = 0.981, P = 0.001), gender (men > women), and marital status of the participants (single > married/partnered and divorced/separated/widowed). Additionally, frequency of fast‐food intake was also found to be significantly associated with perceived convenience of fast food (OR = 1.162, P < 0.001) and dislike toward cooking (OR = 1.119, P < 0.001) but not with perceived unhealthfulness of fast food (OR = 0.692, P = 0.207). These findings suggest public education regarding the unhealthfulness of fast food may not influence fast food consumption. Interventions targeting the issue of convenience and quick or efficient preparation of nutritious alternatives to fast food could be more promising.     

Automatic identification of the number of food items in a meal using clustering techniques based on the monitoring of swallowing and chewing

The number of distinct foods consumed in a meal is of significant clinical concern in the study of obesity and other eating disorders. This paper proposes the use of information contained in chewing and swallowing sequences for meal segmentation by food types. Data collected from experiments of 17 volunteers were analyzed using two different clustering techniques. First, an unsupervised clustering technique, Affinity Propagation (AP), was used to automatically identify the number of segments within a meal. Second, performance of the unsupervised AP method was compared to a supervised learning approach based on Agglomerative Hierarchical Clustering (AHC). While the AP method was able to obtain 90% accuracy in predicting the number of food items, the AHC achieved an accuracy >95%. Experimental results suggest that the proposed models of automatic meal segmentation may be utilized as part of an integral application for objective Monitoring of Ingestive Behavior in free living conditions.     

Eating Frequency is Associated With Energy Intake but Not Obesity in Midlife Women

Midlife women tend to gain weight with age, thus increasing risk of chronic disease. The purpose of this study was to examine associations between overweight/obesity and behavioral factors, including eating frequency, in a cross‐sectional national sample of midlife women (n = 1,099) (mean age = 49.7 years, and BMI = 27.7 kg/m²). Eating behaviors and food and nutrient intakes were based on a mailed 1‐day food record. BMI was calculated from self‐reported height and weight, and level of physical activity was assessed by self‐reported questionnaire. After exclusion of low‐energy reporters (32% of sample), eating frequency was not associated with overweight/obesity (P > 0.05) and was not different between BMI groups (normal, 5.21 ± 1.79; overweight, 5.16 ± 1.74; obese, 5.12 ± 1.68, P = 0.769). Adjusted logistic regression showed that eating frequency, snacking frequency, breakfast consumption, eating after 10 pm and consuming meals with children or other adults were not significantly associated with overweight/obesity. Total energy intake increased as eating frequency increased in all BMI groups, however, obese women had greater energy intake compared to normal weight women who consumed the same number of meals and snacks. Intake of fruit and vegetables, whole grains, dietary fiber, dairy, and added sugars also increased as eating frequency increased. While eating frequency was not associated with overweight/obesity, it was associated with energy intake. Thus, addressing total energy intake rather than eating frequency may be more appropriate to prevent weight gain among midlife women.     

Ecological consequences of scaling of chew cycle duration and daily feeding time in Primates

Feeding systems and behaviors must evolve to satisfy the metabolic needs of organisms. This includes modifications to feeding systems as body size and metabolic needs change. Using our own data and data from the literature, we examine how size-related changes in metabolic needs are met by size-related changes in daily feeding time, chew cycle duration, volume of food processed per chew, and daily food volume intake in primates. Increases in chew cycle duration with body mass in haplorhine primates are described by a simple power function (cycle time α body mass^0.181). Daily feeding time increases with body mass when analyzed using raw data from the “tips” of the primate phylogenetic tree, but not when using phylogenetically independent contrasts. Whether or not daily feeding time remains constant or increases with body mass, isometry of ingested bite size and the slow rate of increase in chew cycle time with body size combine to allow daily ingested food volume to scale faster than predicted by metabolic rate. This positive allometry of daily ingested food volume may compensate for negative allometry of nutrient concentration in primate foods. Food material properties such as toughness and hardness have little impact on scaling of chew cycle durations, sequence durations, or numbers of chews in a sequence. Size-related changes in food processing abilities appear to accommodate size-related changes in food material properties, and primates may alter ingested bite sizes in order to minimize the impacts of food material properties on temporal variables such as chew cycle duration and chew sequence duration.     

Higher 24‐h Respiratory Quotient and Higher Spontaneous Physical Activity in Nighttime Eaters

We have previously shown that a higher 24‐h respiratory quotient (24‐h RQ) predicts greater ad‐libitum food intake and that nighttime eaters (NE) ingested more calories during an in‐patient food intake study and gained more weight over time. We investigated whether 24‐h RQ was higher in individuals who exhibited nighttime eating behavior. Healthy nondiabetic Pima Indians (PI; n = 97, 54 male/43 female) and whites (W; n = 32, 22 male/10 female) were admitted to our Clinical Research Unit. After 3 days of a weight maintaining diet, 24‐h energy expenditure (24‐h EE), 24‐h RQ, rates of carbohydrate (CHOX) and lipid oxidation (LIPOX), and spontaneous physical activity (SPA) were measured in a metabolic chamber whereas volunteers were in energy balance and unable to consume excess calories. Individuals subsequently ate ad libitum from a computerized vending machine for 3 days with amount and timing of food intake recorded. Fifty‐five individuals (36%; 39 PI, 16 W) were NE, who ate between 11 pm and 5 am on at least one of the 3 days on the vending machines. There were no differences in BMI or percentage body fat between NE and non‐NE. After adjusting for age, sex, race, fat‐free mass, fat mass, and energy balance, NE had a higher 24‐h RQ (P = 0.01), higher CHOX (P = 0.009), and lower LIPOX (P = 0.03) and higher 24‐h SPA (P = 0.04) compared to non‐NE. There were no differences in adjusted 24‐h EE or sleep RQ between the groups. Individuals with nighttime eating behavior have higher 24‐h RQ, higher CHOX and lower LIPOX, a phenotype associated with increased food intake and weight gain.     

Effect of Alginate on Satiation,Appetite, Gastric Function,and Selected Gut Satiety Hormones in Overweight and Obesity

Lack of control of food intake, excess size, and frequency of meals are critical to the development of obesity. The stomach signals satiation postprandially and may play an important role in control of calorie intake. Sodium alginate (based on brown seaweed Laminaria digitata) is currently marketed as a weight loss supplement, but its effects on gastric motor functions and satiation are unknown. We evaluated effects of 10 days treatment with alginate or placebo on gastric functions, satiation, appetite, and gut hormones associated with satiety in overweight or obese adults. We conducted a randomized, 1:1, placebo‐controlled, allocation‐concealed study in 48 overweight or obese participants with excluded psychiatric comorbidity and binge eating disorder. All underwent measurements of gastric emptying (GE), fasting, and postprandial gastric volumes (GVs), postprandial satiation, calorie intake at a free choice meal and selected gut hormones after 1 week of alginate (three capsules vs. matching placebo per day, ingested 30 min before the main meal). Six capsules were ingested with water 30 min before the GE, GV, and satiation tests on days 8–10. There were no treatment group effects on GE or volumes, gut hormones (ghrelin, cholecystokinin (CCK), glucagon‐like peptide‐1 (GLP‐1), peptide YY (PYY)), satiation, total and macronutrient calorie intake at a free choice meal. There was no difference detected in results between obese and overweight patients. Alginate treatment for a period of 10 days showed no effect on gastric motor functions, satiation, appetite, or gut hormones. These results question the use of short‐term alginate treatment for weight loss.     

Lack of evidence for a marked endogenous component determining food intake in humans during forced desynchrony

In an attempt to investigate the relative importance of endogenous and exogenous factors in determining food intake, 14 healthy subjects were studied while living in an Isolation Unit (where external time cues were absent) for eighteen 28 h "days" (equal to 21 solar days). The subjects were free to spend their waking time as they chose, and they had a free choice of what they ate and when they ate it. The only restrictions were that no naps were allowed in the "daytime," that some time was required to perform a variety of tests at regular intervals throughout the 18.67 h waking periods, and that any food preparation had to be performed by the subjects themselves. Core (rectal) temperature and activity were monitored throughout, and the subjects answered a questionnaire on their eating habits at 3 h intervals during the waking periods. The questionnaire investigated reasons for eating or not eating a meal during the previous 3 h and, if a meal had been eaten, its type, the factors influencing that choice, and the subjects' subjective responses (hunger before, enjoyment during, and satiety after) to it. The results were analyzed (two-way ANOVA) in terms of both the imposed day length (the exogenous component) and the free-running period of the temperature rhythm (the endogenous component). Results indicated that by far the main reason for eating/not eating was hunger/lack of hunger rather than factors such as food availability and time-pressure. There were statistically significant effects of time within the imposed waking periods upon the type of meal eaten--"breakfast" tending to be a snack, "lunch" a small hot meal, and the "evening meal" a large hot meal. Hot meals (whether small or large) were associated with more hunger before the meal, more enjoyment of the meal, and a greater degree of satiety afterward than were cold meals. These effects suggest that the individuals adjusted their eating habits to fit in with the imposed wake times. By contrast, the effect of circadian phase upon food intake, the type of meal eaten, and subjective responses to the meal was much weaker, and either statistically nonsignificant (P > 0.10) or only marginally so (0.10 > P > 0.05). For example, a large hot meal was chosen as readily for an "evening meal," and subjective responses to it were the same, at whatever circadian phase it was eaten. We conclude that food intake during forced desynchronization is dominated by the waking schedule rather than by circadian influences; some of the implications of these findings when eating habits and the metabolism of food are concerned, particularly in night workers, are considered briefly.     

Association of eating frequency with body fatness in pre- and postmenopausal women

Objective: To examine associations between eating frequency (EF) and body fatness in pre‐ and postmenopausal women, after excluding potential low‐energy reporters. Research Methods and Procedures: In this cross‐sectional study of 220 free‐living women, 64 pre‐ and 50 postmenopausal non‐low‐energy‐reporting women were further analyzed (age, 24 to 74 years; BMI, 18.5 to 38.6 kg/m²). Anthropometric and body composition measurements (DXA) were performed in all study participants. EF, energy, and macronutrient intake were assessed by 3‐day food record. Physical activity level and energy expenditure were assessed by self‐reported questionnaire. Results: No association between EF and adiposity indices was detected in premenopausal women. In contrast, EF was positively correlated with percentage body fat in postmenopausal women (r = 0.30, p = 0.03). EF was positively correlated with total energy intake in both groups and with total energy expenditure in premenopausal women only (r = 0.34, p = 0.02). Multivariate analysis revealed that, in postmenopausal women, EF was a significant predictor of body fatness (standardized β = 0.41, p = 0.01). Discussion: Frequent eating was not found to be related to adiposity in premenopausal women, but it was associated with increased body fat in postmenopausal women. Possible explanations could be that the frequent eating is not associated with a physically active lifestyle in postmenopausal women or that frequent eating predisposes women after menopause to a higher energy intake by increasing food stimuli and rendering it more difficult for them to control energy balance.     

Bottomless Bowls: Why Visual Cues of Portion Size May Influence Intake**

Objective: Using self‐refilling soup bowls, this study examined whether visual cues related to portion size can influence intake volume without altering either estimated intake or satiation. Research Methods and Procedures: Fifty‐four participants (BMI, 17.3 to 36.0 kg/m²; 18 to 46 years of age) were recruited to participate in a study involving soup. The experiment was a between‐subject design with two visibility levels: 1) an accurate visual cue of a food portion (normal bowl) vs. 2) a biased visual cue (self‐refilling bowl). The soup apparatus was housed in a modified restaurant‐style table in which two of four bowls slowly and imperceptibly refilled as their contents were consumed. Outcomes included intake volume, intake estimation, consumption monitoring, and satiety. Results: Participants who were unknowingly eating from self‐refilling bowls ate more soup [14.7 ± 8.4 vs. 8.5 ± 6.1 oz; F(1,52) = 8.99; p < 0.01] than those eating from normal soup bowls. However, despite consuming 73% more, they did not believe they had consumed more, nor did they perceive themselves as more sated than those eating from normal bowls. This was unaffected by BMI. Discussion: These findings are consistent with the notion that the amount of food on a plate or bowl increases intake because it influences consumption norms and expectations and it lessens one's reliance on self‐monitoring. It seems that people use their eyes to count calories and not their stomachs. The importance of having salient, accurate visual cues can play an important role in the prevention of unintentional overeating.     

Circadian Eating and Sleeping Patterns in the Night Eating Syndrome

Objective: To compare the eating and sleep‐wake patterns of persons with the night eating syndrome (NES) with those of matched control subjects. Research Methods and Procedures: Forty‐six overweight/obese NES subjects (mean age 43.3 ± 9.8 years; 32 women) and 43 similar controls (mean age 39.0 ± 11.0 years; 28 women) wore wrist actigraphs for 7 days and completed sleep and food diaries at home. Results: There was no difference between the total energy intake of the NES and the control subjects, but the pattern of energy intake differed greatly. Relative to control subjects, the temporal pattern of food intake of night eaters was delayed. Food intake after the evening meal, as a proportion of the 24‐hour intake, was more than 3‐fold greater in NES subjects than in controls (34.6 ± 10.1% vs. 10.0 ± 6.9%, p = 0.001). NES subjects had sleep onset, offset, and total sleep duration times comparable with those of controls. NES subjects reported more nocturnal awakenings than did controls (1.5 ± 1.0 per night vs. 0.5 ± 0.5; p < 0.001), and their actigraphically monitored arousals occurred earlier during sleep (at 128 minutes after sleep onset vs. 193 minutes, p = 0.01). NES subjects consumed food on 74% of the awakenings vs. 0% for the controls. Discussion: The pattern of cumulative energy intake of the night eaters suggests a phase delay in energy consumption relative to sleep‐wake times. NES may involve a dissociation of the circadian control of eating relative to sleep.     

The effects of nutritional imbalance on compensatory feeding for cellulose-mediated dietary dilution in a generalist caterpillar

Abstract. The interactive effects of macronutrient balance [protein (P) : carbohydrate (C) ratio] and dietary dilution by cellulose on nutritional regulation and performance were investigated in the generalist caterpillar Spodoptera littoralis (Boisduval). Caterpillars were reared through the final stadium on one of 20 foods varying factorially in macronutrient content (P + C%: 42, 33.6. 25.2 or 16.8%) and P : C ratio (5 : 1, 2 : 1, 1 : 1, 1 : 2 or 1 : 5). The animals compensate by eating more of diluted foods, but suffer reduced nutrient intake in proportion to the degree of dilution. Increase in food intake with dilution is greater on balanced than imbalanced foods and this is reflected in greater reduction of dry pupal mass with dilution in the latter. Whereas dilution results in a reduction in the amount of whichever macronutrient is in excess in the food, by contrast, the ability to compensate for the deficient macronutrient in the food is unaffected by nutrient imbalance. Excess protein intake due to nutritional imbalance (diets with high P : C ratios) results in a regulatory decrease in the efficiency of retention of ingested nitrogen relative to restricted protein intake on oppositely imbalanced foods (low P : C ratios). By contrast, decreased protein intake due to dietary dilution is associated with a non‐regulatory reduction in the efficiency of retention, irrespective of P : C ratio. Dilution is similarly associated with reduced utilization efficiency of ingested carbohydrate. The ecological implications of these results are discussed.     

Influence of Methylphenidate on Eating in Obese Men

Objective: Rapid synaptic dopamine transport or reduced brain dopamine receptor signaling may influence energy intake. Methylphenidate, a dopamine reuptake inhibitor, increases brain synaptic dopamine and produces anorexia, suggesting that it may reduce energy intake. We investigated the effects of two doses of short‐acting methylphenidate on energy intake over one meal in obese adult males. Research Methods and Procedures: Nine obese males (>85th BMI percentile) ingested a placebo or a moderate dose (0.5 mg/kg) or a high dose (1.0 mg/kg) of methylphenidate in a within‐subject double‐blind acute laboratory study. One hour after ingestion, pizza consumption was measured in a naturalistic laboratory setting. Results: Participants reduced energy intake by 23% for the moderate dose vs. the placebo (p < 0.02), but there was no significant difference for the high dose vs. the moderate dose (p > 0.05). Participants consumed 34% fewer kilocalories after ingesting the lowest effective dose of methylphenidate compared with placebo (725.7 ± 404.5 vs.1095 ± 271.1 kcal, p < 0.01). Seven of nine subjects responded to the moderate dose. The increase in perceived drug effect above placebo was correlated with the reduction in energy intake for both the moderate (r = ?0.85, p = 0.004) and the high (r = ?0.75 p = 0.021) doses. Hunger scores were not different across drug doses or placebo before drug administration. Discussion: Methylphenidate reduced energy intake of a highly palatable food over one meal by one‐third in obese adult males. Dopamine transport inhibition may be an effective component of a comprehensive treatment for obesity.     

A comparative study of insect abundance and reproductive success of barn swallows Hirundo rustica in two urban habitats

Few studies have quantified the relative reproductive success of passerines in urban habitats. I studied food availability and reproductive success of barn swallows Hirundo rustica in two urban habitats during 2012–2015. Barn swallows breeding in the town center experienced lower insect densities than those in the town periphery. Lower food availability resulted in reduced feeding rates per capita, lower nestling body mass, longer nestling periods, longer inter‐clutch intervals, fewer first and second brood fledglings and a lower total number of fledglings produced during the breeding season in comparison to barn swallows breeding in the town periphery. I hypothesize that the lower intra‐specific competition for nest sites and fitness advantages linked to the solitary breeding in urban habitats balanced the apparent costs of reproduction in more urbanized habitats.     

Differences in circadian time course and level for the plasma concentrations of glucose,free fatty acids and amino acids between ad lib‐eating and fasting rabbits

Abstract

The entrained rhythm in food approaches, representative of the circadian fluctuation in locomotor and food intake activity was recorded from 12 rabbits eating ad libitum during exposure to an LD 12:12 h‐regimen. They were also subjected to 53 h‐sessions with the same LD alternation, in which blood samples were taken at 2 h‐intervals. During these sessions 6 of them were permitted to eat freely whereas the others were food‐deprived. It appeared that in eating rabbits plasma levels are higher for glucose and a‐amino nitrogen but lower for free fatty acids and, further, that eating specimens exhibit marked circadian fluctuations in the levels of glucose and FFA which are closely correlated with, and probably a consequence of, the circadian rhythm in the amounts of food actually taken up in the course of the sessions. In fasting rabbits, however, the same plasma parameters show rhythms with quite another time course, that can be attributed to the circadian fluctuations in (locomotor) activity and endocrine balance.     

Influence of the subfornical organ on meal-associated drinking in rats

A lesion of the subfornical organ (SFO) may disrupt drinking after a meal of dry chow as it does drinking after intragastric administration of hypertonic saline. Food and water intakes of SFO-lesioned (SFOX) and sham-lesioned rats were measured during 90-min tests following various lengths of food deprivation. During the tests, all rats began eating before they began drinking. After 20-24 h of food deprivation, latency to begin drinking after eating had started was longer for SFOX than for sham-lesioned rats. Plasma osmolality was elevated by 2-3% in both lesion groups at 12 min, the latency for sham-lesioned rats to drink, but SFOX rats nevertheless continued eating and delayed drinking. Eating after shorter 4-h food deprivations and ad libitum feeding produced more variable drinking latencies and less consistent effects of SFO lesion. During 24 h of water deprivation, SFO lesion had no effect on the suppression of food intake and did not affect food or water intakes during the first 2 h of subsequent rehydration. These findings indicate that the SFO is involved in initiating water intake during eating and in determining drinking patterns and the amount of water ingested during a meal.     

The ‘omnivorous badger dilemma’: towards an integration of nutrition with the dietary niche in wild mammals

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Estimation of food intake and ingested energy in Daubenton’s bats (Myotis daubentonii) during pregnancy and spermatogenesis

We studied food intake of and estimated ingested energy in female and male Myotis daubentonii during the periods of pregnancy (period 1, 8 May–4 June) and of intense spermatogenetic activity (period 2, 24 July–22 August) over 8 years (1996–2003) in central Germany. We used radiotelemetry to determine the time spent foraging and marked animals with chemiluminescent light-sticks to determine prey attack rates. Body length, body mass, moisture content, and caloric content of chironomids, the main prey of Daubenton’s bats, were measured to estimate the nightly food intake and, in consequence, energy intake. Pregnant females spent significantly more time foraging than males during period 1 and females during the post-lactation period. In contrast, male foraged longer during the period of highest spermatogenetic activity than during late spring and also significantly longer than post-lactating females. Based on a mean number of 8.3 prey attacks per minute, the time spent foraging, and a capture success rate of either 50 or 92%, calculated intake values with a feeding rate of 7.6 insects per minute (=92% capture success) were more consistent with literature data for other insectivorous bats than that of values calculated on the basis of a capture success rate of 50%. In the high capture-success model, calculated insect intake of female bats was 8.0 g during pregnancy and 4.9 g per day during post-lactation, providing 5.0 and 3.0 kJ of ingested energy per gram body mass per day. Calculated intake of male bats was 3.6 g insects per day during late spring and 8.0 g during period of intensive spermatogenesis, providing 2.6 and 5.7 kJ of ingested energy per gram body mass.