Obesity Behind Hunger? What's Researchers Suggesting
Hunger influences what and how much we eat, but is not the only determinant of our eating behavior. Eating is a very pleasant experience and the rewarding or appetizing properties of food play a major role and can lead to overeating when they over-ride the biological cues that govern hunger and fullness.
Scientists have known that high-protein content meals make people feel more full and reduce food intake, resulting in improvements in weight loss and weight loss maintenance. However, the mechanism responsible remained elusive.
A protein called leptin is released from fat cells and hitches a ride across the blood vessels that feed the brain, known as the "blood-brain barrier." The protein then is in the right place to tell the brain that the body has had enough to eat, to eat less or to burn calories faster. However, among those who are obese, the brain doesn't seem to be getting the message. This could be because the blood-brain barrier doesn't properly transport the leptin or because the brain isn't interpreting the signals properly. Leptin also affects the brain in other ways, compromising learning and memory. Low levels of leptin also could be related to cognitive deficits in disorders like type two diabetes."
Researchers at UCLA have suggested that leptin reduces activation in regions of the brain linked to hunger while enhancing activation in regions linked to inhibition and satiety. The findings suggest possible new therapeutic targets for human obesity, an increasing problem in adults as well as children.
Hormone orexin is known for its role in sleep and hunger. And when orexin stimulated, it activates a protein, HIF-1, long known to stimulate cancerous tumor growth, it in turn increased the expression of a variety of genes dedicated to burning sugar to provide energy for the body. Orexin forces HIF-1 to switch cells to burn sugar using oxygen, which burns sugar faster but more efficiently. This strategy makes sense, they said, in terms of evolution. You need to be active and energetic, especially when you're hungry, so you can search for a meal.
In a study in normal-weight and obese people, the researchers now show that enhanced-protein meals stimulate greater release of PYY than either high-fat or high-carbohydrate meals and result in a greater reduction of hunger. Feeding disorders may result from inappropriate behavioral responses to starvation signals.
The health consequences of obesity and overweight used to be more prevalent among the rich, now the poor are becoming obese/ overweight, he said. Obesity is now longer an urban problem; it is now a common problem in rural areas as well. Both rural and urban China, where people are watching more TV, getting around in motorized vehicles, eating fewer cereals and more animal based foods; obesity/ overweight is spreading fast in China.
The average American family spends 14% of its income on food, compared to 24% in Japan. Japanese people, who have access to a much more comprehensive and integrated public transport system than Americans do, are more physically active - they walk a great deal more. The obesity problem in Japan is growing, but it is much smaller than in the USA.
This relationship between hunger and health problems was unaffected by income. In other words, hunger had a strong effect on children's health no matter what the income level of their families. According to the Center on Hunger and Poverty at Brandeis University and the Food Research and Action Center (FRAC) shows that hungry children are more likely to be ill and absent from school. Hunger has a negative impact on children's ability to learn in school. School-aged children who are hungry cannot concentrate or do as well as others on the tasks they need to perform to learn the basics.
Bsx is the molecular link between spontaneous physical activity and food intake. The scientists suggest Bsx is also needed to enable brain cells to sense and respond to specific hunger signals from the body – without it the mice do not feel hunger. "Differences in Bsx activity between individuals could help explaining why some people are intrinsically more active than others and less susceptible to diet-induced obesity. Bsx might be the key to why the same diet makes one person fat, while leaving another unaffected;” according to the German Institute for Nutrition [DIFE], Potsdam, and the University of Cincinnati.
Researchers at the Monell Chemical Senses Center have demonstrated that genetic susceptibility to diet-induced obesity is due to a reduced capacity to burn fat. Fat is one of the fuels that the body's cells burn to provide energy. This process, known as fat oxidation, takes place inside mitochondria, the cell's power plants for generating energy. If the ability to oxidize fat is impaired, the body's capacity to make energy is reduced. This leads to increased hunger and overeating, as the body tries to increase the amount of energy available to meet its needs.
Prader-Willi syndrome (PWS) is a complex genetic disorder that typically causes low muscle tone, short stature, incomplete sexual development, cognitive disabilities, problem behaviors, and a chronic feeling of hunger that can lead to excessive eating and life-threatening obesity. Features of children with PWS are obesity (Big weight gain between one and six years of age), cognitive impairment, behavior problems, extreme hunger, overeating, obsession with food after infancy, poor muscle tone, and less than normal sex hormones (hypogonadism).
A research, led by University of Leicester found that school staff also cited factors such as poor PE facilities, competition from local food retailers and the intensity of the national curriculum as having a negative effect on pupils' lifestyle. Pupils with limited money to spend on food seemed reluctant to try new foods and saw less healthy options such as chips as better value for money than fruit in terms of satisfying their hunger.
Researchers from Northwestern University and Evanston Northwestern Healthcare (ENH) have pinpointed that a faulty or misaligned body clock, which regulates both sleep and hunger, can wreak havoc on the body and its metabolism, increasing the propensity for obesity and diabetes. The body clock regulates the time we go to bed, the time we get up and the time we get hungry -- these are biological principles not psychological factors. It may be a question of not only how much you eat but what time of day you eat and how that affects the body. Are you eating at a time of day when your system is internally aligned to metabolize the food?
For most women, increases and shifts in weight begin during menopause. On average, women gain about a pound a year during this time. But changing hormone levels associated with menopause aren't necessarily the cause of weight gain. Aging and lifestyle factors play a big role in your changing body composition.
Research shows that people who don't sleep adequately have physiologic abnormalities that may increase appetite and calorie intake. We tend to eat when we’re actually sleepy, because we think fatigue is a sign of hunger.” The level of leptin [an appetite stimulating hormone] falls in subjects who are sleep deprived, which promotes appetite. It suggests that at least one factor in obesity can be sleep deprivation. Poor sleep and sleep deprivation may increase appetite.
Scientists had already identified the part of the hypothalamus area of the brain which regulates appetite. The study from the MRC Clinical Sciences Centre at Imperial College London, said: "Appetite and appetite control are important components of why people put on weight. They found a technique, which uses magnetic resonance imaging, will enable a far greater understanding of why certain people become obese when others do not, and why different people have different appetites and hence the neurons showed increased activity, the contrast agent was taken up, making the neurons 'light up' on the scan. The intensity of this signal decreased as the mouse became less hungry and the neurons became less active.
Study at the University Of Washington School Of Medicine in Seattle examined the relative ability of different nutrient types to suppress ghrelin, which is secreted by the stomach and is the only known appetite-stimulating hormone. Circulating ghrelin levels increase shortly before meals and then decrease promptly after ingestion of food.
"Protein consumption resulted in the greatest suppression of ghrelin over a long period and, interestingly, consumption of carbohydrates resulted in strong ghrelin suppression initially, although subsequent ghrelin levels rebounded well above baseline.” Improving our understanding of the regulation of ghrelin by ingested macronutrients could facilitate rational design of weight-reducing diets;" they concluded.
Because your metabolism slows as you get older, you need about 200 fewer calories a day to maintain your weight as you get into your mid- to late 40s. This shouldn't be a problem if you eat only when hungry and only enough to satisfy your hunger.
Genetics and lifestyle factors such as obesity and physical inactivity can lead to diabetes. One in three people who have diabetes don't know they have it. See a doctor if you have any diabetes symptoms, which include frequent urination, excessive thirst, extreme hunger, unusual weight loss, increased fatigue, irritability, and blurry vision. Be aware of kids' hunger cues. Even babies who turn away from the bottle or breast send signals that they're full. If kids are satisfied, don't force them to continue eating. Reinforce the idea that they should only eat when they're hungry.
Hunger and obesity not only pose separate and distinct health risks, but can coexist in the same household. The obesity pills, which has a staggering bill of $94.3 million USD (47.5 million GBP), indicate how Britain, like many western and industrialized countries, is grappling with an overweight population that could wreak havoc on the nation's health cost.
Orlistat, known by its brand name Xenical, prevents the absorption of some kinds of fat in the intestine. Sibutramine, more popularly known as Reductil, alters chemical messages in the brain to control hunger pangs.
The diabetes medication metformin has shown reduced hunger and food intake in people taking the drug. Some experts stress the importance of eating breakfast and at least two other meals a day to help control hunger. People with insulin resistance or diabetes may need to spread their calories out over a whole day by having small meals and two to three small snacks. (This can also help reduce hunger.)
The real challenge will be to identify new ways of dealing with the new nutrition realities of diet-related chronic diseases while also addressing under-nutrition, food insecurity and hunger. Investment in applied nutrition research will be essential in creating and promoting healthy lifestyle initiatives. Their priority is to end childhood hunger in America ensuring that the nearly 12 million American facing hungers have access to the nutritious food they need to learn, grow and thrive.
Fiber comes in two varieties: soluble fiber dissolves in water, while insoluble fiber does not. Although neither type nourishes the body, they promote health in many ways. It also helps regulate the body's use of sugars, helping to keep hunger and blood sugar in check. Burning calories by exercising is half of the weight control solution.
Researchers are working on a device similar to a pacemaker that could work on a nerve that signals hunger and fullness, working as a treatment for obesity. Proponents of the device say it would be less invasive than gastric bypass surgery but still effective. Several companies are working on such technology right now, and one hopes to have an approved device by 2010…
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