Dietary intervention remains a popular, albeit challenging, approach for combating obesity. In recent years, dietary interventions that increase consumption of medium-chain triglycerides (MCT) instead of long-chain triglycerides (LCT) have gained attention. Pre-clinical research has demonstrated that rats fed a high-fat diet (HFD) induce adiposity, but a dietary shift from LCT to MCT suppresses this effect. To date, the extent to which this effect operates via suppressed hyperphagia is not fully understood. In the present study, we sought to determine how consuming a HFD composed of different fat types affects energy intake, adiposity, and hippocampal brain-derived neurotropic factor (BDNF) levels. Rats were assigned to one of four diet groups – rat chow (CHOW), LCT-enriched HFD (LCT-HFD), MCT-enriched HFD (MCT-HFD), or coconut oil-enriched HFD (COCO-HFD), which composes a mixture of LCT and MCT. In Experiment 1, all animals were given <i>ad libitum</i> access to their assigned diet, whereas in Experiments 2 and 3, HFD-subjects were pair-fed to CHOW to prohibit hyperphagia. In Experiments 1 and 2, subjects were aged 20-24 weeks, whereas in Experiment 3, subjects were aged 10-11 weeks. Across experiments, we found that the effect of MCT consumption on suppressing HFD-induced adiposity is causally related to suppressed HFD-induced hyperphagia. Additionally, we failed to detect an effect of HFD consumption on hippocampal BDNF. Therefore, our findings did not support or oppose the hypothesis that MCT consumption attenuates HFD-induced BDNF deficiency. Future studies should focus on determining the causal relationship between MCT consumption, energy expenditure, and HFD-induced adiposity.

Obesity prevalence continues to increase worldwide, yet few safe and effective treatment options are available suggesting there needs to be a greater emphasis on preventing rather than treating obesity. This research investigated the association of obesity predisposing SNPs and a gene score with nutrient consumption patterns including total energy intake and macronutrient distribution in a European ancestry population as well as discussing an evolutionary perspective on eating disorders using current epidemiological evidence to identify genes which may be involved. The association of two of the 14 obesity predisposing SNPs and the gene score with BMI was confirmed in the EpiDREAM population. Novel associations between two SNPs located in or near BDNF (rs6265 and rs1401635) were found with total fat, MUFA, and PUFA intake. Rs1401635 was also associated with total energy and trans fat intake. Novel associations of rs6235 (PCSK1) and the gene score were found with total energy intake. The novel associations found indicate that food related behaviours are one of the mechanisms of action through which obesity predisposing SNPs cause obesity and therefore warrant further investigation. The lack of association among all genes and the modest association of the gene score show that mechanisms other than food consumption are important. The investigation of the evolutionary history of eating disorders revealed that the adapted to flee famine hypothesis is a plausible theory explaining anorexia nervosa while the thrifty genotype hypothesis provides a possible explanation for bulimia nervosa and binge eating disorder. These evolutionary theories can be applied to identify new candidate genes as well as phenotypic traits to investigate to better understand the genetic architecture of eating disorders. Understanding genes associated with disordered eating patterns may highlight future areas for obesity prevention. / Thesis / Master of Science (MSc) / A large percentage of the risk of developing obesity or an eating disorder (anorexia nervosa, bulimia nervosa, and binge eating disorder) is determined by genetics. For obesity, many genes have been identified as influencing risk, but the mechanisms through which the genes work are largely unknown. For eating disorders, gene identification efforts have been mostly unsuccessful and no mechanisms of action have been determined. In the first component of this thesis we found an association between previously identified obesity risk genes and food intake, specifically the total number of calories consumed per day and the percentage of calories from total fat and fat subtypes. These results support that food related behaviours are possible mechanisms of action which need to be further investigated. In the second half of the thesis we viewed eating disorder behaviours from an evolutionary perspective. We concluded that there are theories that possibly explain eating disorder behaviours including being able to live off of small quantities of food as well as binging. These evolutionary theories can be applied to identify new genes to study in the context of eating disorders as well as different definitions of eating disorders.

<p>  </p> <p>Appetitive sensations are widely viewed as important signals for eating decisions. Intra- and inter-individual variability have been reported in short-term studies, but it is still unknown whether individual differences are consistent over time and, whether individuals at the appetite extremes vary in energy intake. Therefore, a seventeen-week observational study was conducted to examine the stability of appetitive sensations (hunger, fullness, and thirst), implications of individual differences in appetite on energy intake and eating patterns, as well as associations between appetitive sensations and selected individual characteristics (age, gender, BMI). </p> <p>Ninety-seven (90 completers) healthy adults recorded the intensity of their hunger, fullness, and thirst hourly during all waking hours and reported their energy intake  for three days at weeks 1, 9 and 17. There were marked and stable inter-individual differences for each sensation over the 17 weeks: hunger (ANOVA, p<0.001, correlation coefficients of ratings between weeks: week 1 vs week 9, r=0.72 (p<0.001), week 1 vs week 17, r=0.67 (p<0.001), week 9 vs week 17, r=0.77 (p<0.001)), fullness (ANOVA, p<0.001, correlation coefficients of ratings between weeks: week 1 vs week 9 r=0.74 (p<0.001), week 1 vs week 17, r=0.71 (p<0.001), week 9 vs week 17, r=0.81 (p<0.001)), and thirst (ANOVA, p<0.001, correlation coefficients of ratings between weeks: week 1 vs week 9 r=0.82 (p<0.001), week 1 vs week 17, r=0.81 (p<0.001), week 9 vs week 17, r=0.88 (p<0.001)). Cross-correlation functions revealed energy intake and eating pattern exerted stronger effects on appetitive sensations than the reverse. However, the absolute effect sizes of the directional effects were small. No robust effects of the studied individual characteristics (gender, age, BMI) were observed. The primary finding is that acute and chronic sensations of hunger, fullness and thirst are stable across individuals, but are poor predictors of energy intake. </p> <p>This dissertation focuses on the study above, but as part of the training experience, two additional studies were conducted. One entailed appetite concept training to improve the validity of appetite measurements. A potential barrier to accurate appetite measurement is low conceptual understanding by study participants and resulting poor sensitivity and accuracy of responses. While each appetitive sensation is independent and has a unique definition, reported similar patterns between appetitive sensations in multiple studies raise questions about whether participants fully comprehend appetite concepts and provide accurate responses. To overcome this potential limitation, appetite concept materials were developed, and two groups of individuals were provided training either with these materials or unrelated sensory information followed by measurement of appetite responses to five different pre-loads. This study terminated early due to the COVID-19 pandemic and thus we cannot draw a conclusion for now due to the limited number of participants.  </p> <p>A second study sought to gain insights on the sensory qualities of fatty acids as part of an effort to determine if oral fat detection is based, in part, on gustatory cues. It has been argued that if fat taste is a primary, the sensations imparted by fats should yield unique percepts and these may be determined by fatty acid chain length. In particular, because acids impart a sour taste, free fatty acids may simply be detected as sour. The fat taste study entailed measurement of intensity ratings with or without sour adaptation (to assess sour notes), tongue locations of taste detection, and subjective descriptors of fatty acids. This study examined intensity and quality ratings of NEFA's ranging from C2 to C18. Oral sites and the time course of sensations were also monitored. Given all NEFA contain carboxylic acid moieties capable of donating hydrogen ions, the primary stimulus for sour taste, testing was conducted with and without sour adaptation to explore the contribution of sour taste across the range of NEFA. Short chain NEFA (C2-C6) were rated as predominantly sour, and this was diminished in C2 and C4 by sour adaptation. Medium chain NEFA (C8-C12) were rated as mainly irritating with long chain NEFA (C18) described mostly as bitter. The latter may reflect the lack of “fatty” lexicon to describe the sensation. Short chain NEFA were mostly localized to the anterior tongue and were of rapid onset. The sensation from medium chain NEFA was attributed to the lateral tongue while medium and long chain NEFA sensations were predominantly localized to the back of the tongue and throat and had a longer lag time. The findings indicate there is a systematic transition of NEFA taste quality and irritation with increments in chain length and this is consistent with multiple modes of transduction.</p>

Children’s energy requirements may vary during school and summer camp days. To evaluate energy balance during these two periods, seventy-eight children (45% females, 8–10 years) living in Parma, Italy, were enrolled in this observational study. Participants completed a 3-day food diary and wore an activity tracker for three consecutive days during a school- and a summer camp-week to estimate energy intake (EI) and energy expenditure (TEE). Height and body weight were measured at the beginning of each period to define children’s weight status. BMI and EI (school: 1692 ± 265 kcal/day; summer camp: 1738 ± 262 kcal/day) were similar during both periods. Both physical activity and TEE (summer camp: 1948 ± 312; school: 1704 ± 263 kcal/day) were higher during summer camp compared to school time. Therefore, energy balance was more negative during summer camp (−209 ± 366 kcal/day) compared to school time (−12 ± 331 kcal/day). Similar results were observed when males and females were analyzed separately but, comparing the sexes, males had a higher TEE and a more negative energy balance than females, during both periods. The results strongly suggest that an accurate evaluation of children’s energy balance, that considers both diet and physical activity, is needed when planning adequate diets for different situations.

No description available.

O exercício físico e a alimentação adequada apresentam estreita relação. O triatlon é uma modalidade que apresenta elevada demanda energética por associar três diferentes tipos de exercício. Objetivos -Verificar a adequação do valor energético total em relação ao dispêndio energético diário, a adequação de macronutrientes da alimentação em relação à recomendação e a contribuição de complemento nutricional. Métodos - Foi mensurado peso corporal de triatletas adultos, de ambos os sexos, a fim de predizer o dispêndio energético diário. Para análise da alimentação foi utilizado diário alimentar de três dias e, para obtenção do dispêndio energético diário, optou-se pelo diário de atividade física de três dias, proposto por Bouchard et al. (1983). Análise estatística - Para análise dos dados utilizou-se estatística descritiva com medidas de tendência central (média e mediana) e dispersão (desvio-padrão, valores mínimos e máximos), teste de Wilcoxon e t-Student. Os resultados foram analisados ao nível de 5% de significância. Resultados - Os 22 triatletas avaliados apresentam idade entre 20 e 45 anos (33±6 anos). O complemento nutricional foi utilizado por 95,4% dos atletas. Dentre os complementos, 76,2% eram compostos à base de carboidrato, 71,4% bebida esportiva, 33,3% compostos protéicos, 9,5% vitamínico-minerais e lipídicos. A alimentação forneceu, em média, 2.800 kcal/dia e, a alimentação associada ao complemento nutricional, representou 3.000 kcal/dia. A maioria dos atletas (90,9%) consumiu proteína em quantidades elevadas, 72,7% ingeriram carboidratos em quantidades inferiores ao recomendado e, 57,7% ingeriram lipídios adequadamente, considerando-se somente a alimentação. Com complemento nutricional, observa-se o mesmo desequilíbrio de macronutrientes. O dispêndio energético diário médio foi de 3.490 kcal, sendo que 83,4% dos atletas apresentam dispêndio maior do que a ingestão alimentar, na ausência de complemento. Conclusões - A alimentação destes triatletas é insuficiente para atender o dispêndio energético diário; o consumo de proteína é superior ao recomendado; o consumo de carboidratos é inferior ao recomendado; o consumo de lipídios é adequado; o uso de complemento nutricional é pratica habitual por triatletas e não contribui de forma estatisticamente significativa para atingir às necessidades energéticas e recomendações de carboidratos (p>0,05), embora contribua para o aumento das proteínas e, alteração do percentual de lipídios de forma significativa (p&#8804;0,05). / Physical exercise and proper diet are closely related, since what is eaten influences physical performance. Triathlon has a high energy demand as it is associated to three types of exercise. Objectives - To find the suitability of the energy intake in relation to the daily energy expenditure, suitability of macronutrients in food in relation to the recommendation of and the contribution of nutritional supplements. Methods - The body weight of adult triathletes of both sexes was measured in order to forecast the daily energy expenditure. A daily food intake of a three day period was used for diet analysis. The daily physical activity of a three day period was used to obtain the daily energy expenditure as proposed by Bouchard et al. (1983). Statistical Analysis - For the analysis of data, descriptive statistics was used with center tending measurements (average and median) and dispersion (standard deviation, minimum and maximum values), Wilcoxon and t-Student tests. The results were analyzed at the level of 5% significance. Results - The 22 triathletes were aged between 20 and 45 (age 33±6). Nutritional supplements were used by 95.4% of the athletes, of which: 76.2% of carbohydrates base compound, 71.4% sport drinks, 33.3% protein compound, 9,5% vitamin-minerals and lipids. The diet supplied on average 2.800 kcal/day and, with the nutritional supplements, 3.000 kcal/day. Of all the triathletes, 90,9% consumed high quantities of protein, 72,7% had intake of carbohydrates below the recommended level and 57,7% ingested lipids in adequate quantities, taking only food into account. With nutritional supplements, the same unbalance of macronutrients was observed. The average daily energy expenditure was 3.490 kcal, with 83,4% of the athletes showing a higher consumption than food intake in the absence of the supplements. Conclusions - The diet of these triathletes is insufficient to meet the daily energy expenditure; consumption of protein is higher than the recommended quantity; consumption of carbohydrates is lower than the recommended quantity; consumption of lipids is adequate; use of nutritional supplements is habitual to the triathletes and do not contribute in a statistically significant manner to achieve the energy requirements and carbohydrates recommendation (p>0,05), although they contribute to an increase of proteins and a change of the lipid percentage (p&#8804;0,05).

O exercício físico e a alimentação adequada apresentam estreita relação. O triatlon é uma modalidade que apresenta elevada demanda energética por associar três diferentes tipos de exercício. Objetivos -Verificar a adequação do valor energético total em relação ao dispêndio energético diário, a adequação de macronutrientes da alimentação em relação à recomendação e a contribuição de complemento nutricional. Métodos - Foi mensurado peso corporal de triatletas adultos, de ambos os sexos, a fim de predizer o dispêndio energético diário. Para análise da alimentação foi utilizado diário alimentar de três dias e, para obtenção do dispêndio energético diário, optou-se pelo diário de atividade física de três dias, proposto por Bouchard et al. (1983). Análise estatística - Para análise dos dados utilizou-se estatística descritiva com medidas de tendência central (média e mediana) e dispersão (desvio-padrão, valores mínimos e máximos), teste de Wilcoxon e t-Student. Os resultados foram analisados ao nível de 5% de significância. Resultados - Os 22 triatletas avaliados apresentam idade entre 20 e 45 anos (33±6 anos). O complemento nutricional foi utilizado por 95,4% dos atletas. Dentre os complementos, 76,2% eram compostos à base de carboidrato, 71,4% bebida esportiva, 33,3% compostos protéicos, 9,5% vitamínico-minerais e lipídicos. A alimentação forneceu, em média, 2.800 kcal/dia e, a alimentação associada ao complemento nutricional, representou 3.000 kcal/dia. A maioria dos atletas (90,9%) consumiu proteína em quantidades elevadas, 72,7% ingeriram carboidratos em quantidades inferiores ao recomendado e, 57,7% ingeriram lipídios adequadamente, considerando-se somente a alimentação. Com complemento nutricional, observa-se o mesmo desequilíbrio de macronutrientes. O dispêndio energético diário médio foi de 3.490 kcal, sendo que 83,4% dos atletas apresentam dispêndio maior do que a ingestão alimentar, na ausência de complemento. Conclusões - A alimentação destes triatletas é insuficiente para atender o dispêndio energético diário; o consumo de proteína é superior ao recomendado; o consumo de carboidratos é inferior ao recomendado; o consumo de lipídios é adequado; o uso de complemento nutricional é pratica habitual por triatletas e não contribui de forma estatisticamente significativa para atingir às necessidades energéticas e recomendações de carboidratos (p>0,05), embora contribua para o aumento das proteínas e, alteração do percentual de lipídios de forma significativa (p&#8804;0,05). / Physical exercise and proper diet are closely related, since what is eaten influences physical performance. Triathlon has a high energy demand as it is associated to three types of exercise. Objectives - To find the suitability of the energy intake in relation to the daily energy expenditure, suitability of macronutrients in food in relation to the recommendation of and the contribution of nutritional supplements. Methods - The body weight of adult triathletes of both sexes was measured in order to forecast the daily energy expenditure. A daily food intake of a three day period was used for diet analysis. The daily physical activity of a three day period was used to obtain the daily energy expenditure as proposed by Bouchard et al. (1983). Statistical Analysis - For the analysis of data, descriptive statistics was used with center tending measurements (average and median) and dispersion (standard deviation, minimum and maximum values), Wilcoxon and t-Student tests. The results were analyzed at the level of 5% significance. Results - The 22 triathletes were aged between 20 and 45 (age 33±6). Nutritional supplements were used by 95.4% of the athletes, of which: 76.2% of carbohydrates base compound, 71.4% sport drinks, 33.3% protein compound, 9,5% vitamin-minerals and lipids. The diet supplied on average 2.800 kcal/day and, with the nutritional supplements, 3.000 kcal/day. Of all the triathletes, 90,9% consumed high quantities of protein, 72,7% had intake of carbohydrates below the recommended level and 57,7% ingested lipids in adequate quantities, taking only food into account. With nutritional supplements, the same unbalance of macronutrients was observed. The average daily energy expenditure was 3.490 kcal, with 83,4% of the athletes showing a higher consumption than food intake in the absence of the supplements. Conclusions - The diet of these triathletes is insufficient to meet the daily energy expenditure; consumption of protein is higher than the recommended quantity; consumption of carbohydrates is lower than the recommended quantity; consumption of lipids is adequate; use of nutritional supplements is habitual to the triathletes and do not contribute in a statistically significant manner to achieve the energy requirements and carbohydrates recommendation (p>0,05), although they contribute to an increase of proteins and a change of the lipid percentage (p&#8804;0,05).

Insufficient sleep may be associated with obesity via increased energy intake and/or decreased energy expenditure. The present study therefore aimed to investigate effects of sleep restriction on energy balance in healthy young adults. Participants (14 men, 13 women) aged 35.3 ± 1.0 y with 23.6 ± 0.2 kg/m2 BMI completed a randomized, crossover study exposed to short and habitual sleep with 4 wk washout. Controlled diets were provided during the first 4 d, followed by 2 d of ad libitum eating. Ad libitum energy intake, energy expenditure and physical activity level were determined as well as energy balance and body weight. Results showed that ad libitum energy intake (p = 0.031), as well as total fat (p = 0.018) increased after short compared with habitual sleep, but physical activity level, energy expenditure, energy balance, and body weight remained unaffected by sleep duration. In conclusion, sleep deprivation elevates energy intake, which may lead to positive energy balance over time and increase the risk of weight gain and/or obesity.

Insufficient sleep may be associated with obesity via increased energy intake and/or decreased energy expenditure. The present study therefore aimed to investigate effects of sleep restriction on energy balance in healthy young adults. Participants (14 men, 13 women) aged 35.3 ± 1.0 y with 23.6 ± 0.2 kg/m2 BMI completed a randomized, crossover study exposed to short and habitual sleep with 4 wk washout. Controlled diets were provided during the first 4 d, followed by 2 d of ad libitum eating. Ad libitum energy intake, energy expenditure and physical activity level were determined as well as energy balance and body weight. Results showed that ad libitum energy intake (p = 0.031), as well as total fat (p = 0.018) increased after short compared with habitual sleep, but physical activity level, energy expenditure, energy balance, and body weight remained unaffected by sleep duration. In conclusion, sleep deprivation elevates energy intake, which may lead to positive energy balance over time and increase the risk of weight gain and/or obesity.

Diss. (sammanfattning) Uppsala : Univ., 2004. / Härtill 5 uppsatser.