Showing posts with label weight loss. Show all posts
Showing posts with label weight loss. Show all posts

2012-11-23

The Science of Appetite Overeating and Weight Loss

The Science of Appetite - Beating Overeating - YouTube



Want to lose weight but can't stop eating? There's a reason for that. Find out how you can beat the desire to overeat and bring yourself one step closer to being your healthy self!

Ghrelin - What is Ghrelin?

Ghrelin is a hormone produced mainly by P/D1 cells lining the fundus of the human stomach and epsilon cells of the pancreas that stimulates hunger. Ghrelin levels increase before meals and decrease after meals. It is considered the counterpart of the hormone leptin, produced by adipose tissue, which induces satiation when present at higher levels. In some bariatric procedures, the level of ghrelin is reduced in patients, thus causing satiation before it would normally occur.

What is Leptin?

Leptin is a 16 kDa protein hormone that plays a key role in regulating energy intake and energy expenditure, including appetite and metabolism. It is one of the most important adipose derived hormones. The ''Ob(Lep)'' gene (Ob for obese, Lep for leptin) is located on chromosome 7 in humans.

The effects of leptin were observed by studying mutant obese mice that arose at random within a mouse colony at the Jackson Laboratory in 1950. These mice were massively obese and excessively voracious. [...]

Precision Nutrition » Leptin, Ghrelin, Weight Loss: It’s Complicated

Leptin and ghrelin seem to be the big players in regulating appetite, which consequently influences body weight/fat. When we get hungrier, we tend to eat more. When we eat more, obviously, we maintain our body weight or gain that weight back.

Both leptin and ghrelin are peripheral signals with central effects. In other words, they’re secreted in other parts of the body (peripheral) but affect our brain (central).

Leptin is secreted primarily in fat cells, as well as the stomach, heart, placenta, and skeletal muscle. Leptin decreases hunger.

Ghrelin is secreted primarily in the lining of the stomach. Ghrelin increases hunger.

Both hormones respond to how well-fed you are; leptin usually also correlates to fat mass — the more fat you have, the more leptin you produce. Both hormones activate your hypothalamus (a part of your brain about the size of an almond).

And here’s an important point: both hormones and their signals get messed up with obesity.


Scientific Weight Loss Tips - YouTube



Tired of searching for the perfect diet or pill to shed some pounds? Find out the top weight loss tips, with solid science to back them up.

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2011-05-10

Weight Loss Virus

A Virus That Could Help You Lose Weight - PSFK



A new study has found evidence that a virus could be used to convince your brain you aren’t hungry. The study, published in Cell Metabolism, explains how researchers at Johns Hopkins University gave some rats a virus that inhibited hypothalamic neuropeptide Y (NPY), a protein linked to appetite.


Turning 'bad' fat into 'good': A future treatment for obesity?

ScienceDaily (May 5, 2011) — By knocking down the expression of a protein in rat brains known to stimulate eating, Johns Hopkins researchers say they not only reduced the animals' calorie intake and weight, but also transformed their fat into a type that burns off more energy. The finding could lead to better obesity treatments for humans, the scientists report.
[...]
For five weeks, two groups of rats were fed a regular diet, with one group also treated with a virus to inhibit NPY expression and the other left as a control group. At the end of five weeks, the treated group weighed less than the control group, demonstrating that suppression of NPY reduced eating.

GEN | News Highlights: Scientists Claim Region of Hypothalamus Could Represent New Target for Obesity and Diabetes

U.S. team finds knocking out DMH neuropeptide Y increases energy expenditure, reduces food intake, improves insulin sensitivity and triggers brown fat adipogenesis. [V. Yakobchuk/Fotolia.com]

NPY in the arcuate nucleus (ARC) region of the hypothalamus has previously been shown to be involved in energy regulation, report Sheng Bi, M.D., associate professor of psychiatry and behavioral sciences at Johns Hopkins, and colleagues. Meanwhile, observations that DMH lesions result in hypophagia and decreased body weight indicate that this region of the hypothalamus also plays a role in maintaining energy homeostasis.

Although NPY is expressed by neurons within the DMH, its function in this region of the brain remains unclear. NPY in the ARC is under the control of leptin, but NPY in the DMH is leptin-independent, suggesting that different neuronal mechanism are involved.

Cell Metabolism - Knockdown of NPY Expression in the Dorsomedial Hypothalamus Promotes Development of Brown Adipocytes and Prevents Diet-Induced Obesity

Cell Metabolism, Volume 13, Issue 5, 573-583, 4 May 2011
Copyright © 2011 Elsevier Inc. All rights reserved.
10.1016/j.cmet.2011.02.019

Authors
Pei-Ting Chao, Liang Yang, Susan Aja, Timothy H. Moran, Sheng Bi


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