1. This paper is concerned about circadian rhythms and metabolic health, which can be affected by the timing of food intake. Also, the paper is concerned about the affect it has on mice when consuming a large meal before breakfast, and smaller meal for dinner compared to mice who only consumed breakfast. This paper suggests that during inactive period, the consumption of high-fat foods results in weight gain. What they are now concerned about is the timing, and size of the meal being consumed to show if this has an effect on mice.
2. The researchers are trying to figure out if mice that consumed one meal a day (breakfast only), and mice that consumed two meals a day (larger breakfast, smaller dinner) have an effect on obesity, lipid metabolism, and circadian clock gene expression. They are also trying to find out if the timing of these meals has an affect on metabolism, and weight gain. Researchers are trying to find out which diet plan will help mice maintain a normal weight and prevent a surplus amount of adipose tissue accumulation.
3. They conducted this experiment in a lab in Tokyo, Japan with six-week-old ICR mice that were held at a temperature of 22.2 °C, humidity of 60.5%, and under 12h light/12h dark. The researchers conducted experiments which used high-fat diet as free-feeding condition. Because insulin and leptin levels are increased, and adiponectin levels are decreased they measured the levels of serum, leptin, and adiponectin to test for metabolic syndrome.
In wild type mouse there is no effect on food intake, body weight and blood glucose though we give more leptin because here the leptin receptors are constant. But, in ob/ob mouse the food intake, body weight and blood glucose levels are decrease because the presence of leptin receptor. However, in the db/db mouse there is no effect due to the absence of the leptin
Genetic research of obesity was partly successful in establishing obesity in model organisms – rodents where obesity occurs spontaneously together with other pathological aspects (insulin resistance, …). The main cause of monogenic obesity in these model organisms are common mutations always present in only one gene. Results of research on model organisms allowed us to understand biological mechanisms of calorie intake and regulation and maintenance of body weight. The most important insight into obesity was achieved in 1994 after discovery of ob gene encoding for leptin. In two years period, using screening method, candidate homologous genes, selected on genetic study basis on mice, another five genes were identified. Mutations on these genes were found to be the cause of autosomal recessive or dominant monogenic obesity. Products of these genes are leptin and its receptor, proopiomelanocortin (POMC) melanocortin receptor 4 (MC4R) and
The RER of both TRF groups was significantly higher during the feeding phase and significantly reduced during the fasting phase than their ad-lib counterparts. Using 45 mice, Chung and colleagues12 studied an 8-hour high-fat TRF diet over 27 weeks. RER was measured from 6 p.m. to 10 p.m., 10 p.m. to 6 a.m. (TRF period), and 6 a.m. to 6 p.m. RER for the ad-lib group was approximately 0.75 throughout the study. RER for the TRF group was 0.70 from 6 a.m. to 10 p.m. and increased during the TRF period. Comparing the two groups, the RER of the TRF group was significantly lower than the ad-lib group from 6 p.m. to 10 p.m., significantly higher than the ad-lib group during the TRF period, and similar to the ad-lib group from 6 a.m. to 6 p.m. In Moro et al.’s18 8-hour TRF study with 34 men, RER was measured between 6 a.m. and 8 a.m. At the end of the study, the RER decreased significantly in the TRF group compared to baseline (0.83 ± 0.02 to 0.81 ± 0.01). Yet the RER in the TRF group was the same as the ad-lib group (0.83 ± 0.02). Sundaram and Yan13 tested the impact of an 8- and 12-hour high fat TRF diet on RER in mice. The diurnal rhythms of RER oscillations of the TRF groups (ranging from about 0.9 to 0.75 between the feeding and fasting cycles) were improved compared to the high-fat ad-lib mice.
Leptin was more prevalent in the rat on the higher fat diet (figure). Insulin levels were then observed and the higher fat diet rat showed a slightly higher amounts of insulin than the rat on the leaner diet (figure). The difference between the diets an insulin was slight whereas the difference between leptin was greater between the
The medical examiner (ME) or coroner is the person in charge of the forensic investigation of a death that has occurred in his or her area of jurisdiction, whether it is a homicide, suicide, accident, or other suspicious death. He or she has a number of tasks to carry out, chief of which is the determination of the cause and manner of the death through performing an autopsy. The medical examiner also takes charge of the analysis of evidence, works with the police investigating the scene of the crime, and presents evidence in court. In short, the ME is involved in both the medical and a legal side of a forensic investigation. The role of the medical examiner is one that has been evolving since the nineteenth century.
Resting metabolic rate (RMR) as main part of daily energy expenditure (14) has principal role in energy balance. Indeed, resting metabolic rate can effect on adiposity or weight gain(14, 15). Our results demonstrated that RMR/kg had reverse significant correlation with weight, BMI and visceral fat. Some pathogenetic explanation for lower energy expenditure in obese subjects with metabolic syndrome may be the lipotoxic theory, lower levels of uncoupling proteins in mitochondria and genetic polymorphism in them(17)
The expression of leptin by adipose tissue is also influenced by feeding behaviour. Short-term (12 h) or long-term (2 or 8 weeks) overfeeding results in an increase in adipocyte leptin expression and circulating leptin in healthy human subjects. Furthermore, circulating leptin levels show a diurnal pattern and are influenced by gender, age, exercise and glucose uptake (Table 3).
Leptin, which is a peptidic hormone (possessing two or more amino acids), essentially serves as a messenger between the brain and fat tissue, and has been noted to aid in the maintenance of body weight. In many animal models, which include rats and mice, obesity was found to be caused by mutations in the rodents' leptin and leptin receptors, where single mutations (mutations where changes occur to only one nucleotide base) occurred in the coding area or the 5' end of the non-coding region of the leptin gene. This sparked the interests of many scientists, as they began to wonder if mutations in leptin and its receptors may also be responsible for obesity in humans. At first, no evidence was found of this being true, but recently, new research suggests that particular forms of obesity in humans may be the result of mutations of the leptin gene. Early experiments of parabiosis had been done with mice, where two individuals were joined anatomically, and recognized that the lack of leptin was responsible for them having the complex, obese phenotype. Although the ob/ob mice could be treated with leptin, the db/db mice were not affected by the treatment of leptin, having researchers come to the conclusion that the incapability to respond to leptin is the cause of mutations in the leptin receptors.
The effects of nutrition can begin before birth, with the nutrition of the mother. Under nutrition can result in negative effects of the development of the brain that can become permanent and irreversible. One example is the lack of iron, which is a necessary part of the brain’s tissue. When iron deficiency is present nerve impulses tend to move slower. “Iron deficiency…is associated with behavior changes and delayed psychomotor development” (Nutrition and Cognitive Development, 2001), as well as decrease attention span, irritability, fatigue, and difficultly with concentration. “ Anemia is one of the most prevalent nutritional disorders in the world, affecting nearly one
We are required to obtain certain amount of nutrients from food. Food can simply divide into 2 groups, macro-nutrients and micro-nutrients composition. Both of the groups mentioned do affect the metabolism rate. According to Hulbert and Else, dietary fatty acid will affect the metabolism rate and some of the polyunsaturated fatty acid will increase the metabolism rate (1999). Meanwhile, different kinds of animals have their own unique requirement for macro-nutrients, such as proteins, carbohydrates and fat. Moreover, most of the food intake is driven by achieving the required protein intake. Animals on a low protein diet will over eat carbohydrates and fat until the protein requirement has been satisfied. If this case
In many studies done, there has been a common notion that breakfast skipping is highly associated with obesity regardless of culture diversity and race. A majority of the world population has acknowledged this fact and important steps have been taken to correct this habit.
Meal pattern Analysis represents an analytical examination of the distribution of the drinking and feeding episodes over the light-dark cycle and was shown to be altered in several animal models of obesity (Clifton 200, Moran 2003, Cottone et al. 2007). A meal is generally defined by the association of the different intake bouts separated by less than a determined inter-meal interval. Meal pattern analysis provides information about meal number, meal duration, meal size, intermeal interval, eating rate and satiety ratio (Le Magnen and Devos 1980, Moran 2003, Zorilla et al. 2005). The study of feeding pattern is now considered as an indispensable parameter to be evaluated for understanding the principles governing ingesting behaviour and his lost of control (Geary, 2005). At present, if the equipment and tools available for the study of drug consumption
Furthermore, irregular meal time could cause illnesses of insulin resistance and diabetes. Human body actually tries to memorise consumption pattern so that to control the secretion of chemicals in digestive system such as insulin. Irregular consumption makes body sugar rate variable since digestion could not be achieved effectively. Unstable blood sugar concentration would lead to risk of diabetes.
My target area began as a focus on eating more in general. The food available at PSP was not always ideal, many times the food was either unhealthy or there simply weren’t enough options that I enjoyed. As a result, I noticed that my weight began to significantly decline and I desperately wanted to allay this problem. After completing my log sheets over three weeks, I came to the realization that the bulk of my missed meals came in the morning. I would sleep until eight to make sure that I received adequate sleep, however, I realized that in doing this; I was forgoing breakfast which was negatively affecting my health and my performance at Cornell. In fact, “research involving adults and children has indicated that breakfast might enhance memory, attention, the speed of processing information, reasoning, creativity, learning, and verbal abilities” (Consumer Reports). No matter a person’s age, breakfast is a vital part of their life.
As a night owl, staying up late can create bad eating habits. Cutting back on sleep increases the likelihood of indulging high calorie foods which may eventually lead to obesity. As the lead study author at the University of Pennsylvania, Andrea M. Spaeth tested a group of 27 participants who went to bed at 10 pm and another group of 198 who went to bed at 4 am. Their results concluded that the second group had consumed significantly more food than the first group. As Spaeth stated, the longer we stay awake, the more time we get to eat high fat foods.