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Two for One: How Our Brains Reward Us Twice for Every Meal





food reward dopamine

Feel the dopamine. (Credit: Syda Productions/Shutterstock)

Food. It’s probably on your mind quite a bit this holiday season, whether you’re anticipating festive meals or dreading the pounds you might pack on during a bout of epicurean overindulgence.

Though tips on managing our cravings for all things sweet and fatty abound, it’s also worth remembering that the odds are stacked against us when it comes to resisting the call of another slice of pie.

Our brains respond to food, and even the sight or thought of it, with a heady rush of chemicals aimed at convincing us to eat. It’s a relict of bygone days when a steady food supply was no guarantee and the best strategy was to stuff ourselves every chance we got. Our brains evolved to deliver a rush of neurotransmitters to both motivate us to and reward us for eating. Is it any wonder we still enjoy it so much?

Double Feature

And it turns out that we actually get not one but two chemical rewards for satiating ourselves. Using a new imaging technique, a team of researchers led by scientists at the Max Planck Institute for Metabolism Research in Germany have discovered that our brains release the neurotransmitter dopamine in response to a tasty snack both when the food hits our mouths and after it’s entered our stomachs — a real twofer.

With a modified version of a Positron Emission Tomography (PET) scan, the researchers were able to track the movement of dopamine through the brains of 12 participants who had just been given something to eat. Dopamine is part of the brain’s reward system, and it’s released both when we see or think about food and when we actually eat it. The researchers gave the participants either something tasty to eat (a milkshake, of course) or a bland control food (a “tasteless solution”) and watched to see when and where the neurotransmitter appeared.

Dopamine blossomed in the participant’s brains as soon as the milkshake hit their tastebuds, as expected. It was concentrated in areas involving reward-value signaling, memory and inhibitory control, among others — again, no surprise. But, 15 to 20 minutes after the milkshake had gone down the hatch, the researchers found another wave of dopamine in people’s brains. Even more odd, it was in totally different regions than the first rush. This time around, the dopamine appeared in regions related to higher cognitive functions, compared with the more primal areas stimulated in the initial release of the neurotransmitter.

Further analysis picked out another trend: If people had been craving the milkshake, the first rush of dopamine was quite strong, but the second was much smaller. If they hadn’t been craving the milkshake as much, the first release was small, but the second was larger. In short, the people who really wanted a milkshake got a bigger reward when it first hit their tongues. The less milkshake-happy saw a smaller reward at first, but they got a more substantial dopamine hit later on.

The work was published Thursday in Cell Metabolism.

From Tongue to Stomach

It’s a bit of an oversimplification, but the double whammy reflects the fact that our mouths and our stomachs like food for two different reasons. Our mouths like food because it tastes good, and our stomachs like it because it’s full of nutrients. So when we taste something good, our brains reward us with dopamine. And, when our stomachs get the stuff they need to fuel our bodies, they also send signals to the brain telling it to release a chemical “thank you.”

The researchers think that the people who craved milkshakes got more dopamine upfront because their payoff was bigger, and then less later on in an attempt to curb overeating. Those who got a bigger hit later on were seeing their bodies respond to the nutritional value of the food: Their stomachs were simply telling their brains “This is good! Let’s get more!” by rewarding the behavior. It’s proof that our bodies do reward us for eating food that’s good for us, not just stuff that tastes good.

Though the response has been observed in mice, this is the first time it’s even been found in humans. The discovery has implications for how we treat obesity, the researchers say, as it seems that the more we crave food, the less we get rewarded for it later on when our stomachs are counting nutrients. By choosing meals that favor in-the-moment gratification — things with high sugar and fat content — over long-term satisfaction, we’re also forgoing that second dopamine hit, the one actually related to nutritional content. The result could be choices that are less healthy.

If anything, it’s also a reminder that less immediately-satisfying foods do have their own reward. We just have to wait a little to get it.


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Globe Climate: Canada’s resource reckoning is coming





Good afternoon, and welcome to Globe Climate, a newsletter about climate change, environment and resources in Canada.

This afternoon, the Alberta government announced that it is restoring a coal mining policy it revoked last spring. At the time, the move provoked a widespread public backlash detailed by The Globe. The original decision, which opened up more than 1.4 million hectares to exploration, was made without public consultation. Premier Jason Kenney previously defended the changes.

Lots more on coal and Canada’s resources industry in this week’s newsletter edition.

Now, let’s catch you up on other news.

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‘Incredibly destructive’: Canada’s Prairies to see devastating impact of climate change





As the climate continues to warm at an alarming rate, experts warn if dramatic steps to mitigate global warming are not taken, the effects in Canada’s Prairie region will be devastating to the country’s agriculture sector.

According to Environment and Climate Change Canada, the country is warming, on average, about double the global rate.

Scientists with the National Oceanic and Atmospheric Administration in the U.S. recently found 2020 was earth’s second-hottest year on record, with the average land and ocean surface temperature across the globe at 0.98 of a degree C above the 20th-century average.

However, the agency found the northern hemisphere saw its hottest year on record, at 1.28 degrees C above the average.

“(In Canada) we are looking at about 6.4C degrees of warming this century, which isn’t much less than one degree per decade, which is just a terrifying rate of warming,” Darrin Qualman, the director of climate crisis policy and action at the National Farmer’s Union said.

Qualman said there is “massive change coming” to Canada’s Prairies, which will be “incredibly destructive.”

“It’s not going too far to say that if we made that happen, parts of the Prairies wouldn’t be farmable anymore,” he said.

According to the federal government, in 2018 Canada’s agriculture and agri-food system generated $143 billion, accounting for 7.4 per cent of the country’s GDP.

The sector employed 2.3 million people in 2018. The majority of the 64.2 million hectares of farmland in Canada is concentrated in the Prairies and in southern Ontario.

The effects of climate change are already being felt on the ground in the Prairies, Qualman said, adding that the NFU has already heard from farmers complaining of “challenging weather.”

“People are sharing pictures of flattened crops and buildings, et cetera, that have been damaged,” he said. “And we’re still at the beginning of this.”

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Insect-based dog food aims to cut your pet’s carbon pawprint





Meat has an enormous carbon footprint, with livestock liable for about 15 per cent of worldwide emissions, as we have beforehand mentioned on this e-newsletter. That is prompted specialists to suggest consuming much less meat for sustainability (and well being) causes.

However what about your pet? One research discovered that the methane and nitrous oxide emissions generated by canine and cat meals within the U.S. alone had been equal to about 64 million tonnes of CO2, or roughly the quantity produced by 13.6 million automobiles. And it might be getting worse, with a development towards feeding pets “human-grade” meat.

That is prompted some pet meals makers to look to lower-carbon protein sources — together with bugs.

Research present that producing insect-based meals requires far much less feed, land and water and generates far fewer greenhouse fuel emissions per kilogram than meats comparable to beef, pork or rooster.

That is one of many causes increasingly more pet meals containing insect protein are hitting the market. Purina, a model owned by multinational Nestlé, launched a line of canine and cat meals containing black soldier fly larvae in Switzerland in November.

In Canada, Montreal-based Wilder Harrier began promoting canine treats made with cricket protein in 2015 and pet food made with black soldier fly larvae in 2019. It plans to broaden to launch a line of insect-based cat treats later this yr and cat meals in 2022 due to “a ton of demand,” mentioned firm co-founder Philippe Poirier.

Wilder Harrier initially labored with animal nutritionists on insect-based merchandise to unravel a unique downside — specifically, the founders’ canines had allergy symptoms to frequent meats utilized in canine meals. Poirier mentioned now about half its prospects hunt down the product due to their pets’ allergy symptoms and about half for environmental causes.

Dr. Cailin Heinze, a U.S.-based veterinary nutritionist licensed by the American School of Veterinary Vitamin, has written concerning the environmental influence of pet meals. She mentioned we’re typically “not as involved as we probably ought to [be]” concerning the environmental footprint of pets.

Alternatively, she famous that the longer-term influence of newer diets, comparable to vegan meals and people containing bugs, hasn’t been nicely examined in comparison with conventional pet meals.

Maria Cattai de Godoy, an assistant professor of animal sciences on the College of Illinois who research novel proteins for pet meals (together with bugs, yeast and plant-based substances), mentioned such substances are rigorously examined to find out their security and diet earlier than being added to pet meals. 

“This can be a very extremely regulated trade,” she mentioned, however admitted it is also evolving.

Relating to bugs, she mentioned constructive information “reveals promise in direction of utilizing them increasingly more in pet meals.” Insect-based proteins have additionally earned the endorsement of the British Veterinary Affiliation, which says some insect-based meals could also be higher for pets than prime steak.

However Godoy famous that there isn’t any one-size-fits-all resolution, and pet homeowners ought to take into consideration the wants of their very own particular person pet and analysis whether or not a specific weight loss plan can be appropriate.

She mentioned that other than the kind of protein, issues like packaging and manufacturing strategies may also make a distinction. For instance, utilizing meat byproducts that may in any other case turn into waste would not drive elevated meat manufacturing the identical approach as utilizing human-grade meat.

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