A way to banish hunger pangs found
After two decades of research, a Boston-based team has demonstrated how to activate a brain circuit to banish hunger, making dieting a breeze.
“One reason that dieting is so difficult is because of the unpleasant sensation arising from a persistent hunger drive,” says co-senior author Dr. Bradford Lowell of Harvard Medical School. “Our results show that the artificial activation of this particular brain circuit is pleasurable and can reduce feeding in mice, essentially resulting in the same outcome as dieting but without the chronic feeling of hunger.”
The hunger orb
The research team has mapped out the neurocircuitry that controls hunger, eating and appetite.
This led to the important discovery that calorie deficiency is detected by a bundle of hunger-driving neurons in the brain’s hypothalamus called Agouti-peptide-expressing (AgRP) neurons.
Next, the team searched for what brings satiety, which they hypothesized could be a receptor that gets blocked by active AgRP, called melanocortin 4 receptors (MC4Rs).
The magic wand of satiety
To isolate MC4R neurons, the team worked with mice genetically engineered to express the protein in MC4Rs, enabling scientists to control the activity of these neurons.
Turning off the MC4R neurons caused the mice to eat like they were starving — despite their having just consumed a day’s worth of calories.
On the flipside, artificially activating the MC4R neurons quelled hunger in unfed mice, which showed no interest in food, according to the study, published in Nature Neuroscience.
The remaining question was what regulates hunger-satiety cycles, which the team answered by injecting a tracer molecule into the MC4R neurons that allowed them to observe with which cells they communicated in the brain.
How to wave the wand
Observation led to an area in the brain called the lateral parabrachial nucleus (LPBN) which, when they probed MC4R neurons using a laser light as they communicated with the LPBN, curbed the mice’s hunger.
Conflicting theories exist concerning why we eat — some day it’s to banish hunger, others say it’s because the taste of food is rewarding.
The team thus set out to find out whether this neurocircuit, normally activated by eating, would produce a rewarding sensation if artificially activated.
Substituting eating for laser light stimulation of the neurocircuit, the scientists offered both genetically modified mice and control mice the chance to be bathed in blue laser light.
Not surprisingly, the genetically modified mice made efforts to place themselves in the laser light, indicating that stimulating this neurocircuit artificially could be as rewarding as eating.
– AFP Relaxnews
6. CrossFit for kids?
As fitness crazes go, the workout programme CrossFit has some of the most dedicated disciples.
The wildly popular, self-directed programme, which puts a focus on core strength training and conditioning, has built a robust online community, where its participants set goals, share routine variations and track their progress.
Joe Reed, 16, uses a 25-pound weight over his head to do squats during a CrossFit class for teens. Photo: TNS
They’ve even developed their own language: the WOD is the workout of the day, AMRAP is “as many reps as possible” and a C&J is what’s better known to weightlifters as a “clean and jerk”.
It’s safe to say that for many of its followers, CrossFit is a philosophy, as well as a workout regimen.
Chiropractor Patrick Landry, 48, a former college athlete, discovered CrossFit while training for a marathon several years ago. He didn’t feel like he was getting what he needed from his running and his judo practice and decided to give it a try.
He was so pleased with the results that he opened the CrossFit gym in January 2012.
“I know there are a lot of skeptics of CrossFit, and some people call it a cult,” Landry said. “But it creates an emotional anchor for people, emotionally, spiritually and physically. People who have never exercised a day in their lives are learning to control their bodies, to move better and have better flexibility, better coordination and stamina.”
In the fall of 2012, Landry took what he thought was the next logical step: starting a kids programme. He has four children of his own and wanted to give them options besides team sports.
He now has about 30 children who participate regularly and semi-regularly in the programme.
Barry Novotny and his daughter Ainsley, 12, are part of a CrossFit family that goes to Landry’s gym. She uses the training as a supplement, to help her build endurance for cross-country running and the other sports she plays.
“I think the majority of her soccer team does CrossFit as an extracurricular activity,” Barry Novotny said. “We try to go as a family as many nights a week as we can. There’s a real community aspect to it, which makes it more fun for the kids.”
That’s a primary goal for Landry: that the kids participating in the programme aren’t seeing it as one more thing on their already full schedules.
“The way I teach the classes, you can drop in and out, and you don’t have to be here every day,” he said. “There are too many sports where kids are told they have to be there, at practice, at the games, and they get overcommitted.”
The gym is one of the 1,800 CrossFit facilities that teaches the CrossFit Kids programme.
According to the programme’s website, the aim is to “provide an active alternative to sedentary pursuits, which means less childhood obesity and all-around better health for our children.”
Dan Jackson, 16, somersaults during a CrossFit class. Photo: TNS
The CrossFit Kids programme is structured so that it builds mechanics first, then consistency, then adds intensity, which Sara Colley said was a good way to prevent kids from performing exercises before they’re prepared.
She added that a big concern with growing children are growth plate injuries, which can result when children try to do exercises they’re not ready for.
Colley, a physical therapist with UPMC Sports Medicine and the Centers for Rehab Services, said while she has some concerns about inexperienced children possibly injuring themselves with some of the ballistic movements in CrossFit’s weight-lifting routines, like snatches and clean-and-jerk lifts, there are plenty of positive things they can gain from the programme.
“It can be fun, and there’s no emphasis on ‘winning’, which is a great idea,” she said. And, CrossFit can provide an alternative exercise for kids who are involved in only one sport, which can lead to repetitive stress injuries, Colley said.
“If they’re doing CrossFit while they’re taking time away from their sport, that’s a good thing,” she said. “And any time you can boost a kid’s self esteem, that’s good, too. But that requires a good coach.”
She said that was an area of concern for her because according to CrossFit’s website, the training to instruct children consists of a weekend session and a criminal background check but no additional certification or degree, which Colley doesn’t think is sufficient.
Landry said he has a good rapport with the kids in his programme, which he agrees is crucial to their participation.
“If I don’t know how to connect to kids, they won’t respond,” he said. “I want it to be fun for them, for them to want to be here.” – Pittsburgh Post-Gazette/Tribune News Service
Category: Features, Wellness and Complementary Therapies
