Author: Kate Horowitz

You’ve probably heard that yo-yo dieting can backfire. Now we have some idea why: Scientists say that intense food restriction teaches the body to hold on to any calories and fat it can get. The researchers published their findings in the journal Evolution, Medicine, and Public Health.

There are oodles of diets out there, each promising that it alone holds the secret to dropping pounds and keeping them off forever. But almost all these diets are short-term strategies. The weight we lose almost always comes creeping back in as soon as we go back to eating normally.

It’s something of an evolutionary puzzle. If carrying excess weight is physiologically inefficient—that is, it can be taxing for the body—why would our bodies work to regain what we’ve lost?

To find out, two British researchers looked in an unexpected direction: math. Animal behavior scientist Andrew Higginson of the University of Exeter teamed up with University of Exeter mathematician John McNamara to create a mathematical simulation of yo-yo dieting and its effects. Using what they knew about the behavior and physiology of existing animals, including humans, Higginson and McNamara created a hypothetical animal. They set it in a hypothetical natural world that followed the same patterns as our own. The animal had to eat to live, and being active used up energy. The animal’s food supply also fluctuated, as it does for real animals in real habitats. The researchers’ question was this: Would those fluctuations produce long-term changes in the animal’s body?

They certainly did. The simulation results showed that a body in inconsistent conditions like those in which our ancestors evolved would benefit from retaining any fat it could find in times of abundance. The results also suggested that the artificial scarcity created by dieting is a real trigger for this self-protective weight gain. According to the team’s results, on-again, off-again dieters are more likely to put on weight than people who never diet at all. And while this fact may be frustrating, the authors say, it’s actually a sign of a healthy body.

“The best thing for weight loss is to take it steady,” Higginson said in a statement. “Our work suggests that eating only slightly less than you should, all the time, and doing physical exercise is much more likely to help you reach a healthy weight than going on low-calorie diets.”

But please remember: You’re wonderful just the way you are.

We have not been giving our little ones enough credit. Psychologists working with young toddlers say the kids are capable of recognizing when someone else is pretending, cheating, or straight-up lying. The research is published in the Proceedings of the National Academy of Sciences.

Psychologists use a test called the false-belief task to gauge whether a person knows that other people’s thoughts are different from their own. The classic test involves a story in which a protagonist with incomplete or inaccurate information must make a choice between two items. Before the protagonist acts, psychologists ask the person taking the test which item they think the protagonist will select. If the test-taker realizes that their ideas differ from the protagonist’s—that the protagonist has a false belief—they can guess that the protagonist will make the wrong choice.

Kids under the age of 4 generally fail this test, and psychologists generally take this as an indication that younger children don’t understand other people’s thoughts or beliefs. But in doing so they’ve overlooked one major element: their test depends on the test-taker’s ability to understand the questions and articulate a response. Like many tests of cognitive ability, the bias is built right in.

One team of researchers recognized this issue and decided to design a better test. They created a simplified version with pictures and more basic questions, then brought in 144 kids aged 2 and a half. The simplified test made both the testing procedure and the questions themselves easier for the children to understand. They could guess that the protagonist was about to make a mistake. They knew her thoughts were not the same as their own.

Renee Baillargeon of the University of Illinois was a co-author on the study. “Our study shows that when the task is made simpler, even 2-and-a-half year olds succeed,” she said in a statement. “So the ability to answer questions about persons with false beliefs is present very early in development, contrary to what was traditionally thought.”

Co-author Peipei Setoh of Nanyang Technological University noted that this false belief—that little kids weren’t clever enough to figure it out—could be negatively affecting the way we raise them.

“If parents believe that children do not understand complicated matters, they may tell simpler versions of the truth and ‘dumb down’ what they view as complicated content for kids. Parents of young children and early childhood educators should be aware that children’s early cognitive abilities may be more advanced than previously thought.”

Unless you’ve been living under a rock for the last few years, you’ve probably heard about the health benefits of yogurt and other fermented foods. Clinical trials have found that probiotics (helpful bacteria) can help ease a range of symptoms. But what they haven’t found is how, exactly, they work. Now scientists writing in the journal Applied and Environmental Microbiology have got a theory.

The bacterial strain called Lactobacillus paracasei DG grows naturally in our mouths and guts. It’s also a common ingredient in probiotic supplements and so-called functional foods like probiotic yogurt. We’re happy to buy it and consume it, but we don’t know what makes it tick.

Researchers at Italy’s Università degli Studi di Milano and the University of Huddersfield in the UK theorized that L. paracasei DG was secreting some strange chemical compound called an exopolysaccharide (EPS). They searched through the bacterium’s DNA and, sure enough, found genes that make EPS.

The next step was to figure out what kind of EPS it was and what it did. They conducted chemical tests and nuclear magnetic resonance to examine the EPS at a molecular level. They found that a large portion of the compound was made of rhamnose, a sugar commonly found in probiotic strains.

Next, the team administered the EPS to living human immune cells and watched to see how they would react. Because probiotics are often used to ease symptoms of inflammation, it might be expected that the EPS would be a calming influence, but the opposite was true: The presence of the compound triggered a release of inflammatory chemicals from the immune cells.

Coauthor Andrew P. Laws says this seemingly counterintuitive finding actually makes a lot of sense. “We have evidence that our polysaccharides bind to and mildly activate the receptors which release pro-inflammatory messengers,” he said in a statement. “We believe that this generates a lesser inflammatory response than what would occur if the same receptors were activated by pathogenic bacteria.”

It’s a strange strategy, but it’s not completely unheard of. Scientists studying the “mind-control” germ Toxoplasma gondii recently reported that the parasite uses a very similar technique to elude detection within the body of its host.

Some insects’ mouth-to-mouth exchanges transmit tiny molecules of hormones and other important chemical information, according to scientists writing in the journal eLife.

The spit-swapping behavior is called trophallaxis. Many entomologists who witnessed the behavior in ants and other social insects believed the bugs were using it to efficiently share food. But some researchers noticed that carpenter ants were trophallax-ing in non-dining contexts, like when one ant would return to its family after being away. The scientists wondered if the ants’ kissing juice contained more than just calories.

They brought lots of ants into the lab to sample what the ants were sharing. At first, the researchers tried just waiting around until one ant initiated trophallaxis, but that mostly resulted in a lot of waiting and very little fluid. Eventually, they figured out that they could gently squeeze the ants’ bellies until the liquid came dribbling out of their mouths.

The researchers ran chemical and genetic tests on the fluid to determine its contents, and they found all kinds of interesting things. The liquid did indeed include particles of food and digestive enzymes, but it also contained several growth-related proteins and a juvenile hormone that can influence an insect’s development.

To find out how these compounds might affect a trophallaxis recipient, the researchers added the juvenile hormone to the meals they were feeding adult ants. The adults passed the hormone-charged liquid onto their larvae. The larvae loved it. Individuals who had taken in the hormone were twice as likely as others to survive to adulthood.

First author Adria LeBoeuf works at the Center for Integrative Genomics in Switzerland. She says the ants could very well be using trophallaxis to decide which larvae succeed. “When the ants feed their larvae, they aren’t just feeding them food, they are casting quantitative ballots for their colony, administering different amounts of growth-promoting components to influence the next generation,” she said in a statement.

Larvae chosen to receive the liquid are being nourished in more ways than one. In some ways, LeBoeuf says, it’s a lot like mammals’ milk. It also suggests that “…the oral exchange of fluids, such as saliva, in other animals might also serve previously unexpected roles.” Yum.

The future of diabetes medicine may be duck-billed and web-footed. Australian researchers have found a compound in platypus venom (yes, venom) that balances blood sugar. The team published their results in the journal Scientific Reports.

So, about that venom. The platypus (Ornithorhynchus anatinus) may look placid and, frankly, kind of goofy, but come mating season, the weaponry comes out. Male platypuses competing for female attention wrestle their opponents to the ground and kick-stab them with the venom-tipped, talon-like spurs on their back legs. It’s not a pretty sight. But it is an interesting one, especially to researchers.

Animal venoms are incredible compounds with remarkable properties—and many of them make excellent medicine. Many people with diabetes are already familiar with one of them; the drug exenatide was originally found in the spit of the venomous gila monster. Exenatide works by mimicking the behavior of an insulin-producing natural compound called Glucagon-like peptide 1 (GLP-1). The fact that the lizard has both venom and insulin-making genes is not a coincidence; many animal venoms, including the gila monster’s, induce low blood sugar in their prey in order to immobilize them.

It’s a good strategy with one flaw: GLP-1 and compounds like it break down and stop working very quickly, and people who have trouble making insulin really need their drug to keep working.

With this issue in mind, Australian researchers turned their attention to our duck-billed friends. They knew that platypuses, like people, made GLP-1 in their guts, and that platypuses, like gila monsters, make venom. The real question was how these two compounds interacted within a platypus’s body.

The researchers used chemical and genetic analysis to identify the chemical compounds in the guts and spurs of platypuses and in the guts of their cousins, the echidnas.

They found something entirely new: a tougher, more resilient GLP-1, one that breaks down differently—and more slowly—than the compounds in gila monster spit. The authors say this uber-compound is the result of a “tug of war” between GLP-1’s two uses in the gut and in venom.

“This is an amazing example of how millions of years of evolution can shape molecules and optimise their function,” co-lead author Frank Gutzner of the University of Adelaide said in a statement.

“These findings have the potential to inform diabetes treatment, one of our greatest health challenges, although exactly how we can convert this finding into a treatment will need to be the subject of future research.”

If you think construction noise is a nap-destroying nuisance, you should check out the space rock that hit a sleeping woman on this day in 1954.

Ann Hodges had settled onto the couch that afternoon with no awareness of the agent of chaos tearing through the heavens above her house. A larger-than-average meteorite was zipping toward our planet, crumbling as it fell. The fireball produced by the meteorite’s disintegration was so bright it could be seen by humans below in three different states. Most of the rock’s bulk was vaporized as it entered Earth’s atmosphere, but one bowling-ball-sized chunk survived and continued on its improbable course.

The scorching-hot rock crashed through the roof of Hodges’s home in Sylacauga, Alabama, then through her ceiling into her living room, bouncing off a large radio before slamming into her unconscious body. Astonishingly, 34-year-old Hodges survived the incident with minor injuries, including a heinous bruise on her waist. But the meteorite’s violent arrival was just the start.

Everyone wanted a piece of the space-struck housewife—Hodges made appearances in newspapers, LIFE magazine, and on TV game shows—but they also wanted a piece of the rock that struck her. Air Force intelligence seized the rock to make sure it wasn’t some sort of spy equipment. Geologists at the Smithsonian wanted to keep it for further study. Ann’s husband Hewlett saw the meteorite as a gold mine and decided to sell it.

Unfortunately, their landlord Bertie Guy had the same idea. The two took it to court, where Guy argued that any celestial object that fell on her property automatically belonged to her. The case became a battle of endurance. Eventually, the landlord lost, but not before the drawn-out legal process drove down the meteorite’s value. By the time the rock reverted to Ann and Hewlett’s possession, nobody wanted to buy it. Ann began using it as a doorstop, and eventually donated it to the Alabama Museum of Natural History.

The trauma of the incident, legal battles, and overwhelming media attention left their scars on Hodges long after her bruise had healed. She and her husband separated, citing the strain caused by the meteorite and saying they wished it had never happened. Ann fell ill and died just eight years later at the age of 52.

Hodges’s brush with space was, oddly enough, not the beginning nor the end of her home state’s relationship with meteorites. The jazz standard “Stars Fell on Alabama” was penned 20 years earlier in praise of an especially spectacular meteor shower. Six decades later, another meteorite rained debris not too far from the couple’s old home. If this story has a moral, it’s for Alabama residents: Please keep an eye on the sky. 

We started from the branches; now we’re here. Researchers say the remains of the human ancestor nicknamed “Lucy” include heavily built arms and weaker legs more like those of tree-dwelling chimpanzees than like those of modern humans. They published their findings in the journal PLOS One.

Lucy’s remains have captivated scientists since they were first unearthed in Ethiopia in 1974. She and other Australopithecus afarensis were the first human ancestors to walk upright. Aside from this, Lucy’s day-to-day life has remained something of a mystery, as has her death.

Some researchers think she met her demise after falling out of a tree. A controversial study published earlier this year concluded that a fracture in Lucy’s upper arm could have been caused by a fall from a great height. Project leader John Kappelman said Lucy’s transitional existence may have been her downfall. “It may well have been the case that adaptations that permitted her to live more efficiently on the ground compromised her ability to move safely in the trees — and may have predisposed her kind to more falls,” Kappelman told Science magazine.

Not everyone agreed. “Terrestrial animals like antelopes and gazelles, elephants and rhinos and giraffes — all these bones show very similar fracture and breakage patterns as Lucy,” paleoanthropologist Don Johanson, a discoverer of Lucy, noted in Science. “You can be sure they didn’t fall out of trees.”

Now, Kappelman and his colleagues are picking up the other end of the story. Computed tomography (CT) scans of Lucy’s bones showed greater density in her arms than in her legs, which suggests she was using her upper limbs far more often.

“It is a well-established fact that the skeleton responds to loads during life, adding bone to resist high forces and subtracting bone when forces are reduced,” Kappelman said in a statement. “Tennis players are a nice example: Studies have shown that the cortical bone in the shaft of the racquet arm is more heavily built up than that in the nonracquet arm.”

Kappelman believes his team’s new findings support his earlier hypothesis. “It may seem unique from our perspective that early hominins like Lucy combined walking on the ground on two legs with a significant amount of tree climbing,” says Kappelman, “but Lucy didn’t know she was ‘unique’—she moved on the ground and climbed in trees, nesting and foraging there, until her life was likely cut short by a fall—probably out of a tree.”

Toxoplasma gondii, a parasitic protozoan, infects more than 50 percent of people on Earth and millions of cats and other animals, yet the secrets to its success have largely remained a mystery—until now. A new study published in the journal Structure concludes that the parasite can hack into and rewire its host’s immune system to suit its own purposes.

You may not recognize this parasite by name, but you’ve probably heard it mentioned. T. gondii infection, better known as toxoplasmosis, has the power to produce strange changes in its hosts. The parasite can only reproduce within a cat’s body, and scientists believe that it can manipulate other animals to make that happen. Mice with toxoplasmosis lose their healthy fear of cats and will stroll right up to their predators, essentially delivering their parasitic passengers directly into the mouth of the beast.

Some scientists believe that toxoplasmosis can also influence human behavior, and studies have linked infection to symptoms of schizophrenia, bipolar disorder, and intermittent explosive disorder. Other researchers say these findings are overhyped, overblown, and impossible to reproduce.

Whether or not T. gondii can change our minds, it’s definitely changing our bodies. Toxoplasmosis can be dangerous for pregnant women and people with compromised immune systems, but most people never even know they’re sick—which is not how our bodies are supposed to work. Our immune systems are supposed to protect us from parasites like T. gondii, or, if they can’t, at least alert us by getting riled up and inflamed.

But somehow, this intruder found a way to override our personal security systems. The first clue to its strategy came last year, when scientists at the Institute for Advanced Biosciences discovered that T. gondii makes a protein called GRA24 that in turn convinces the body to make an inflammatory protein called p38α.

This raised a new question, one which became the focus of the new study: Why would a parasite ever want to trigger inflammation?

The researchers cultured human cells in the laboratory, then gave them toxoplasmosis and monitored the molecular-level interactions between the two proteins. They discovered that GRA24 can essentially hot-wire the security system and bypass multiple steps of the immune response process. By making its own p38α, T. gondii can control the flow and extent of inflammation. It doesn’t shut down the immune system; doing so could make its host sick and jeopardize the parasite’s new, cushy existence. Instead, it muffles the system just enough to keep itself safe and undetectable.

Watch your back, T. gondii. We’re on to you.

The zero-G lifestyle does funny things to our bodily fluids. That’s the conclusion of one recent study, which may have found a reason for a common space travelers’ malady. The researchers presented their results [PDF] at the annual meeting of the Radiological Society of North America.

If we’re going to start sending humans to Mars and other distant destinations, we’re going to need to know if we can survive the trip. So astronauts are an incredible scientific resource, not only for what they do while in space, but also for what they experience. Living in orbit can shrink astronauts’ hearts and stretch their spines. It can also damage their ability to see: Numerous travelers who left Earth with 20/20 vision have returned to find they need glasses just to read or drive.

“People initially didn’t know what to make of it, and by 2010 there was growing concern as it became apparent that some of the astronauts had severe structural changes that were not fully reversible upon return to earth,” lead author Noam Alperin of the University of Miami said in a statement.

Scientists call the phenomenon visual impairment intracranial pressure, or VIIP. The name is slightly misleading in its certainty. Researchers think the eye problems are the result of increased pressure inside astronauts’ heads, but they haven’t really been sure.

Alperin and his colleagues wondered if the problem might not be liquid—cerebrospinal fluid (CSF), to be precise. CSF is a crucial component of healthy brain and body function. It surrounds our brains and spinal cords and acts kind of like amniotic fluid in the womb, ensuring a flow of nutrients and removing waste. CSF is also somewhat adaptable and responds to changes in the position and angle of your body and head. It’s a good system, and it works.

At least where there’s gravity. The research team scanned the brains and eyeballs of seven different astronauts both before and after long stints aboard the International Space Station (ISS). They compared those scans with results from another nine astronauts who had only been on the ISS briefly.

There could be no doubt about it—longer stays in space were messing with the astronauts’ eyes. Their eyes were more flattened; their optic nerves showed more swelling; and, most interestingly, they had higher volumes of CSF in their eye sockets and in the CSF-producing part of the brain. The higher the CSF volume, the more trouble an astronaut had seeing.

“The research provides, for the first time, quantitative evidence obtained from short- and long-duration astronauts pointing to the primary and direct role of the CSF in the globe deformations seen in astronauts with visual impairment syndrome,” Alperin said.

Identifying the source of the problem is the first step to correcting it. Alperin and NASA are now working to simulate the conditions that cause VIIP so they can figure out how to protect astronauts’ eyes in the future.

The Federal Trade Commission (FTC) has had it with marketers of homeopathic products. The agency has ruled [PDF] that all homeopathic products must now be labeled with a warning that there is no scientific evidence that they actually work.

The theory behind homeopathy is, itself, a little hard to swallow. Practitioners believe that whatever causes an illness must also be able to cure it, and that diluting a chemical can transform it from toxin to treatment. But even if that were true, the homeopathic products on store shelves today are so watered down that you’d need to take hundreds of thousands of doses in order to ingest a single molecule of the so-called active ingredient.

Scientists have been studying homeopathic remedies for as long as people have been using them, yet they’ve found no evidence that these products are any better than a placebo. These products cannot do what they say they can do—but until now, they’ve been allowed to go on saying it anyway.

The U.S. Food and Drug Administration regulates, well, food and drugs. Herbal supplements and other so-called natural remedies are largely outside their purview. This lack of government oversight has enabled the explosion of a multi-billion-dollar industry in which an untested bottle of pills could claim to cure anything from cellulite to cancer.

The FTC can’t do anything about a drug’s efficacy or safety, but it can do something about all those unsubstantiated claims. The agency released a 24-page report [PDF] on homeopathy advertising and sales that concluded, “No convincing reasons have been advanced …  as to why efficacy and safety claims for OTC homeopathic drugs should not be held to the same truth-in-advertising standards as other products claiming health benefits.”

The agency’s new ruling gives homeopathic product marketers two choices: Either they can stop making unsubstantiated claims about their products, or they can add a warning to their drugs’ packaging. The warnings must communicate that a) there is no scientific evidence that the product works; and b) that the claims made on the package are based on outdated, unproven theories that are not accepted by modern scientists or doctors.

Telling consumers the truth is a step in the right direction, although it may be too little too late. Numerous studies have shown that we don’t actually read or heed a package’s disclaimers. The FTC’s own report found that 25 to 45 percent of consumers believed that a sample product had been approved by the FDA. They continued to believe this even after reading a warning on the package that clearly stated the opposite.

“It’s embarrassing to admit because it sounds like people are stupid,” advertising lawyer Rebecca Tushnet told Slate in 2014. “In fact, people are human. They have limiting processing capacity, and you can’t just stuff information down their gullet.”

You’re a smart reader (we know this because you’re on our site). If you want to avoid getting ripped off, apply those savvy reading skills the next time you’re in the pharmacy.