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The keto diet helps men – not women – lose weight, new research suggests
One group of women still seem to benefit from the popular diet.
- Medical professionals and dieters have long noticed differences in the efficacy of the keto diet between the sexes.
- A new study suggests that estrogen plays a role in preventing women from losing weight on the keto diet.
- More research is needed before scientists know exactly how the keto diet's effects vary between the sexes.
It's long been observed that men seem to have an easier time than women in terms of losing weight on the keto diet. The results of a new study on the keto diet's effects on mice support that anecdotal claim, suggesting that sexual hormones might prevent the high-fat diet from helping females lose weight.
At the annual meeting of the Endocrine Society on Sunday, researchers from the University of Iowa discussed a soon-to-be-published study showing how female mice on the keto diet were less likely than males to lose weight, and more likely to experienced impaired blood sugar control.
In the experiments, researchers put a group of mice on the keto diet or a regular diet, which served as the control.
- Keto diet: 75 percent fat, 3 percent carbs, 8 percent protein
- Regular diet: 7 percent fat, 47 percent carbs, 19 percent protein
After 15 weeks on the keto diet, the male mice experienced losses of body weight and body fat, while the female group actually gained weight. The researchers speculated that estrogen might be interfering with the weight-loss process, so they removed ovaries from some of the mice. This caused females to start experiencing the same weight-loss effects observed in the male group.
"Our studies suggest that sex hormones might modulate the way that male versus female mice respond to ketogenic diets," lead investigator Jesse Cochran, a research assistant at the University of Iowa, told Inverse.
The male mice experienced another, less desirable change: Their livers showed stronger signs of fibrosis — the thickening and scarring of connective tissue — and fatty storage than the female mice. The males had higher levels of a hormone called FG21, which previous studies have shown is released in response to liver damage.
Is the keto diet bad for the liver?
The intuitive answer might be yes, considering the keto diet calls for eating lots of fats, and having too much fat (particularly triglycerides) in your liver can lead to inflammation and cell death. However, some research suggests that a responsibly implemented keto diet can actually improve liver health.
For example, a 2018 study tracked the effects of the keto diet on 10 mildly obese people with fatty livers. Ann Fernholm, science journalist and founder of the not-for-profit Dietary Science Foundation, said the study offered an "extremely detailed map showing what happens when a person cuts down on sugar and starch in their diet.
"The liver metabolism changed almost immediately," she wrote for Diet Doctor. "Instead of creating fat, it started burning it and already in the first day you could see a significant reduction in liver fat. As a great side effect, the participants also improved their cholesterol profiles. The microbiome also changed. A surprising discovery was that it started producing more folic acid, a vitamin which is important in the liver's metabolism. Low levels of folic acid has earlier been associated with an increased risk of fatty liver."
Still, more research is needed
Despite its popularity, there's still much scientists don't know about the keto diet, and most medical professionals stop short of recommending the diet unless it's prescribed to epileptics.
"The keto diet is primarily used to help reduce the frequency of epileptic seizures in children," said registered dietitian Kathy McManus, director of the Department of Nutrition at Harvard-affiliated Brigham and Women's Hospital. "While it also has been tried for weight loss, only short-term results have been studied, and the results have been mixed. We don't know if it works in the long term, nor whether it's safe."
The mixed results on keto diet studies could be explained, in part, by discrepancies in efficacy between the sexes, and a lack of solid research on how females respond to the diet.
"Most studies of the ketogenic diet for weight loss have taken place in small numbers of patients or in only male mice, so sex-based differences in response to this diet are unclear," said senior investigator E. Dale Abel, M.D., Ph.D., chair of the University of Iowa Department of Internal Medicine and president-elect of the Endocrine Society.
Regarding the recent research, it remains unclear whether similar studies conducted with human participants would yield the same results.
Can the keto diet work for some women?
Interestingly, the recent study suggests it can.
"[The finding that ovariectomized mice experienced weight loss] suggests that postmenopausal women could potentially experience better weight loss outcomes with the ketogenic diet compared to younger women," Cochran said.
This seems to match the observations of some medical professionals prior to the recent research.
"My anecdotal observation in my medical office and working with people online is that men perform better in nutritional ketosis compared with women, particularly women aged 40 and older," wrote Sara Gottfried, a board-certified gynecologist, on her website. "My female patients, myself included, have more problems on keto with their stress hormones (i.e. producing too much cortisol), thyroid function, and may develop menstrual irregularities. At the root of these problems is dysfunction of the control system for hormones, the hypothalamic-pituitary-adrenal-thyroid-gonadal (HPATG) axis."
Since the initial use of ketogenic diets (KD) as adjunctive treatment for epilepsy, these diets are being increasingly used to promote weight loss and to reduce the risk of metabolic sequelae of severe obesity. Typical KD are very low in carbohydrate and high in fat, promoting hepatic production of ketone bodies. Most animal studies tend to be performed in male mice, and few studies have evaluated gender differences in response to KD. To explore sex differences in response to KD, female and male wild-type mice on the C57BL/6J background were fed either a control diet (CD- 7% fat, 47% carb., 19% protein) or KD (75% fat, 3% carb., 8% protein), following weaning. Females on the CD manifested higher levels of circulating β-hydroxybutyrate (β-HB) than males (2.86-fold, p<0.05). Circulating β-HB concentrations increased with KD in males and females (1.30-fold & 5.05-fold, p<10-4& p<0.01 respectively) with higher concentrations in females. After 15 weeks of feeding, females on KD displayed an increase in body weight (1.07-fold KD vs. CD, p<0.05) while body weight declined in males (0.88-fold, p<0.05). Nuclear magnetic resonance (NMR) analysis revealed elevated lean mass in 18-week old females (1.07-fold, p<0.05), but a significant reduction in fat mass in males (0.49-fold, p<0.05) relative to sex-matched mice on CD. The female mice on KD developed impaired glucose tolerance with a 1.35-fold increase in glucose tolerance test area under the curve (GTT AUC) (p<0.001) relative to CD females. In contrast, fasting glucose levels were lower in males on KD (131.8 ± 12.5 mg/ dl vs. 169.2 ± 6.3 mg/dl, p<0.05). Despite no significant change in GTT AUC, the male mice on KD displayed elevated blood glucose concentrations 30 minutes after injection relative to males on CD (344.9 ± 18.7 mg/ dl vs. 272.0 ± 10.31 mg/dl, p<0.05). However, after 120 minutes, blood glucose levels returned to initial levels. To further investigate the role of estrogen in this sexual dimorphism, female mice were ovariectomized (OVX) and randomized to receive either a CD or KD after weaning. At 15 weeks old, OVX mice on KD displayed decreased body weight (0.84-fold, p<0.0001) and fat mass (0.65-fold, p<0.001) relative to CD-fed mice. Despite changes in body composition, OVX mice on KD still exhibited impaired glucose tolerance with a 1.4-fold increase in GTT AUC comparable to OVX mice on CD (p<0.05). In conclusion, significant sex differences exist in terms of body composition and metabolism in response to ketogenic diet, which may partially be attributed to estrogen.
What is human dignity? Here's a primer, told through 200 years of great essays, lectures, and novels.
- Human dignity means that each of our lives have an unimpeachable value simply because we are human, and therefore we are deserving of a baseline level of respect.
- That baseline requires more than the absence of violence, discrimination, and authoritarianism. It means giving individuals the freedom to pursue their own happiness and purpose.
- We look at incredible writings from the last 200 years that illustrate the push for human dignity in regards to slavery, equality, communism, free speech and education.
The inherent worth of all human beings<p>Human dignity is the inherent worth of each individual human being. Recognizing human dignity means respecting human beings' special value—value that sets us apart from other animals; value that is intrinsic and cannot be lost.</p> <p>Liberalism—the broad political philosophy that organizes society around liberty, justice, and equality—is rooted in the idea of human dignity. Liberalism assumes each of our lives, plans, and preferences have some unimpeachable value, not because of any objective evaluation or contribution to a greater good, but simply because they belong to a human being. We are human, and therefore deserving of a baseline level of respect. </p> <p>Because so many of us take human dignity for granted—just a fact of our humanness—it's usually only when someone's dignity is ignored or violated that we feel compelled to talk about it. </p> <p>But human dignity means more than the absence of violence, discrimination, and authoritarianism. It means giving individuals the freedom to pursue their own happiness and purpose—a freedom that can be hampered by restrictive social institutions or the tyranny of the majority. The liberal ideal of the good society is not just peaceful but also pluralistic: It is a society in which we respect others' right to think and live differently than we do.</p>
From the 19th century to today<p>With <a href="https://books.google.com/ngrams/graph?year_start=1800&year_end=2019&content=human+dignity&corpus=26&smoothing=3&direct_url=t1%3B%2Chuman%20dignity%3B%2Cc0" target="_blank" rel="noopener noreferrer">Google Books Ngram Viewer</a>, we can chart mentions of human dignity from 1800-2019.</p><img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDg0ODU0My9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTY1MTUwMzE4MX0.bu0D_0uQuyNLyJjfRESNhu7twkJ5nxu8pQtfa1w3hZs/img.png?width=980" id="7ef38" class="rm-shortcode" data-rm-shortcode-id="9974c7bef3812fcb36858f325889e3c6" data-rm-shortcode-name="rebelmouse-image" />
American novelist, writer, playwright, poet, essayist and civil rights activist James Baldwin at his home in Saint-Paul-de-Vence, southern France, on November 6, 1979.
Credit: Ralph Gatti/AFP via Getty Images
The future of dignity<p>Around the world, people are still working toward the full and equal recognition of human dignity. Every year, new speeches and writings help us understand what dignity is—not only what it looks like when dignity is violated but also what it looks like when dignity is honored. In his posthumous essay, Congressman Lewis wrote, "When historians pick up their pens to write the story of the 21st century, let them say that it was your generation who laid down the heavy burdens of hate at last and that peace finally triumphed over violence, aggression and war."</p> <p>The more we talk about human dignity, the better we understand it. And the sooner we can make progress toward a shared vision of peace, freedom, and mutual respect for all. </p>
Scientists find that bursts of gamma rays may exceed the speed of light and cause time-reversibility.
- Astrophysicists propose that gamma-ray bursts may exceed the speed of light.
- The superluminal jets may also be responsible for time-reversibility.
- The finding doesn't go against Einstein's theory because this effect happens in the jet medium not a vacuum.
Jet bursting out of a blazar. Black-hole-powered galaxies called blazars are the most common sources detected by NASA's Fermi Gamma-ray Space Telescope.
Cosmic death beams: Understanding gamma ray bursts<div class="rm-shortcode" data-media_id="cu2knVEk" data-player_id="FvQKszTI" data-rm-shortcode-id="c6cfd20fdf31c82cb206ade8ce21ba3f"> <div id="botr_cu2knVEk_FvQKszTI_div" class="jwplayer-media" data-jwplayer-video-src="https://content.jwplatform.com/players/cu2knVEk-FvQKszTI.js"> <img src="https://cdn.jwplayer.com/thumbs/cu2knVEk-1920.jpg" class="jwplayer-media-preview" /> </div> <script src="https://content.jwplatform.com/players/cu2knVEk-FvQKszTI.js"></script> </div>
Is Bitcoin akin to 'digital gold'?
- In October, PayPal announced that it would begin allowing users to buy, sell, and hold cryptocurrencies.
- Other major fintech companies—Square, Fidelity, SoFi—have also recently begun investing heavily in cryptocurrencies.
- While prices are volatile, many investors believe cryptocurrencies are a relatively safe bet because blockchain technology will prove itself over the long term.
Presentation slide from Sanja Kon's presentation on the evolution of money at 2020 Web Summit
Credit: Sanja Kon<p>The move came shortly after the payments company Square invested $50 million into Bitcoin, and after Fidelity announced that it was opening a Bitcoin fund into which qualified purchasers could invest <a href="https://www.bloomberg.com/news/articles/2020-08-26/fidelity-launches-inaugural-bitcoin-fund-for-wealthy-investors" target="_blank">(minimum investment: $100,000)</a>. Together, this institutional backing might have something to do with Bitcoin's recent surge back to near its 2017 price peak of $19,783. (Bitcoin is listed at 19,384.30 as of Dec. 3.)<br></p>
Presentation slide from Sanja Kon's presentation on the evolution of money at 2020 Web Summit
Credit: Sanja Kon<p>But more importantly, it suggests cryptocurrencies might soon have the opportunity to prove themselves in real-world use cases. After all, skeptics have long doubted the ability of cryptocurrencies to go mainstream as a form of everyday payment. But people seem increasingly comfortable with digital payment systems.</p><p style="margin-left: 20px;">"The entire world is going to come into digital first," Schulman said at Web Summit, adding that PayPal's services already go hand-in-hand with cryptocurrencies. "As we thought about it, digital wallets are a natural complement to digital currencies. We've got over 360 million digital wallets and we need to embrace cryptocurrencies."</p><p>Sanja Kon, vice president of global partnerships at the cryptocurrency payments processor company UTRUST, also spoke at Web Summit about the increasing adoption of digital payments:</p><p style="margin-left: 20px;">"Physical cash is becoming more and more obsolete. And the next step in the evolution is digital currency."</p><p>Kon noted some of the inherent advantages of cryptocurrencies, namely ownership. </p><p style="margin-left: 20px;">"For many people, this is really the main benefit of cryptocurrency: Users owning cryptocurrencies are able to control how they spend their money without dealing with any intermediary authority like a bank or a government, for example," Kon said, adding that there are no bank fees associated with cryptocurrencies, and that international transaction fees are significantly lower than wire transfers of fiat currency.</p><p>Kon said cryptocurrencies have unique growth opportunities in areas where people aren't integrated into modern banking systems:</p><p style="margin-left: 20px;">"With cryptocurrencies and blockchain, with the use of just a smartphone and access to internet, Bitcoin and cryptocurrencies can be available to populations of people and users without access to the traditional banking system."</p>
Bitcoin as 'digital gold'<p>Still, it could take years for people to start using cryptocurrencies for everyday purchases on a large scale. Despite this, many cryptocurrency advocates see digital currencies, particularly Bitcoin, as a way to store value—digital gold, essentially.</p><p style="margin-left: 20px;">"I don't think Bitcoin is going to be used as a transactional currency anytime in the next five years," billionaire investor Mike Novogratz recently told <a href="https://www.bloomberg.com/news/articles/2020-10-23/novogratz-says-bitcoin-is-digital-gold-not-a-currency-for-now?srnd=markets-vp" target="_blank">Bloomberg</a>. "Bitcoin is being used as a store of value. [...] "Bitcoin as a gold, as digital gold, is just going to keep going higher. More and more people are going to want it as some portion of their portfolio."</p><p>There are obvious parallels between gold and Bitcoin: Both are mined, do not degrade over time, are finite in supply, and aren't directly tied to the value of fiat currency, making them <a href="https://www.reuters.com/article/us-gold-inflation/gold-as-an-inflation-hedge-well-sort-of-idUSKCN1GD516" target="_blank" rel="noopener noreferrer">relatively invulnerable to inflation</a>. The obvious objection is that the price of Bitcoin, and cryptocurrencies in general, is far more volatile than gold.</p><p>But for investors who believe the inherent value of cryptocurrency technology will prove itself over the long term, these price fluctuations are just bumps on the long road to the future of currency. </p><p style="margin-left: 20px;">"It's no longer a debate if crypto is a thing, if Bitcoin is an asset, if the blockchain is going to be part of the financial infrastructure," Novogratz said. "It's not if, it's when, and so every single company has to have a plan now."</p>
Singapore has approved the sale of a lab-grown meat product in an effort to secure its food supplies against disease and climate change.
Approve for your dining pleasure<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="dd3f57f8baf14e654812d30a309d1f17"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/307gysA18_E?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p><a href="https://www.ju.st/en-us" target="_blank" rel="noopener noreferrer">Eat Just</a>, a company that produces animal-alternative food products, announced the news earlier this week. In what the company is calling a world first, Singapore has given it permission for a small-scale commercial launch of their GOOD Meat brand product line. For the initial run, the cultured chicken meat will be sold as an ingredient in "chicken bites."</p><p>"Singapore has long been a leader in innovation of all kinds, from information technology to biologics to now leading the world in building a healthier, safer food system. I'm sure that our regulatory approval for cultured meat will be the first of many in Singapore and in countries around the globe," Josh Tetrick, co-founder and CEO of Eat Just, <a href="https://www.businesswire.com/news/home/20201201006251/en/Eat-Just-Granted-World%E2%80%99s-First-Regulatory-Approval-for-Cultured-Meat" target="_blank" rel="noopener noreferrer">said in a release</a>.</p><p>According to the release, Eat Just underwent an extensive safety review by the Singapore Food Agency. It provided officials "details on the purity, identity and stability of chicken cells during the manufacturing process, as well as a detailed description of the manufacturing process which demonstrated that harvested cultured chicken met quality controls and a rigorous food safety monitoring system." It also demonstrated the consistency of its production by running more than 20 cycles in its 1,200-liter bioreactors.</p><p>While Eat Just did not offer details on its propriety process, it likely follows <a href="https://www.newscientist.com/article/mg24032080-400-accelerating-the-cultured-meat-revolution/" target="_blank" rel="noopener noreferrer">one similar to other lab-grown meats</a>. It starts with muscle cell samples drawn from a living animal. Technicians then isolate stem cells from the sample and culture them <em>in vitro</em>. These cultured stem cells are then placed in a bioreactor, essentially a fermenter for fleshy cells. The bioreactor contains scaffolding materials to keep the growing tissue from falling apart as well as a growth material—the sugars, salts, and other nutrients the tissue needs to grow. As the cells grow, they begin to differentiate into the muscle, fat, and other cells of meat tissue. Once grown, the tissues are formed into a meat product to be shipped to restaurants and supermarkets.</p>
An abattoir abatement?<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDg2Mjg5OS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyODg1NDI3N30.AYmFJfWQbPjK-o1IatyFHL-OLjcfXBMmQKYyvz4oT3s/img.jpg?width=980" id="8a82d" class="rm-shortcode" data-rm-shortcode-id="93f824fe4c6f397ab2b65e4665847e71" data-rm-shortcode-name="rebelmouse-image" />
A graph showing the number of animals slaughtered in the United States per year from 1961–2018.
Credit: Our World in Data<p>Singapore's approval is an important step in support for clean meats—so-called because they don't require animal slaughter and would likely leave a reduced carbon footprint—but hurdles remain before widespread adoption is possible.</p><p>The most glaring is the price. The first lab-grown hamburger was eaten in London in 2013. <a href="https://www.bbc.com/news/science-environment-23576143" target="_blank" rel="noopener noreferrer">It cost roughly $330,000</a>. As with any new technology, investment, iteration, and improved manufacturing will see the price drop substantially and quickly. For comparison, Eat Just's chicken will be priced equivalent to premium chicken.</p><p>Other hurdles include up-scaling production, <a href="https://www.nature.com/articles/d41586-019-00373-w" target="_blank" rel="noopener noreferrer">the need for further research</a>, and developing techniques to reliably produce in-demand meats such as fish and beef. Finally, not all countries may be as receptive as Singapore. Countries with large, entrenched meat industries may protect this legacy industry through a protracted and difficult regulatory process. Though, the meat industry itself is investing in lab-grown meat. Tyson Foods, for example, has <a href="https://euromeatnews.com/Article-Tyson-Foods-announces-investment-in-clean-meat/697" target="_blank" rel="noopener noreferrer">invested in the food-tech startup Memphis Meats</a>, the company that debuted the world's first beef meatball.</p><p>"I would imagine what will happen is the U.S., Western Europe and others will see what Singapore has been able to do, the rigours of the framework that they put together. And I would imagine that they will try to use it as a template to put their own framework together," <a href="https://www.reuters.com/article/us-eat-just-singapore/singapore-approves-sale-of-lab-grown-meat-in-world-first-idUSKBN28C06Z" target="_blank" rel="noopener noreferrer">Tetrick told Reuter's during an interview</a>.</p><p>Regardless of the challenges, the demand for meat substitutes is present and growing. In 2020, plant-based substitutes like Beyond Meat and Impossible foods <a href="https://bigthink.com/coronavirus/plant-based-meat" target="_self">gained a significant foothold in supermarkets</a> as meat-packing factories became coronavirus hotspots. The looming threat of climate change has also turned people away from meat as animal products. Livestock production is environmentally taxing and leaves <a href="http://css.umich.edu/factsheets/carbon-footprint-factsheet" target="_blank" rel="noopener noreferrer">a much larger carbon footprint</a> than grain and vegetable production. </p><p>Then there's the moral concern of animal cruelty. In 2018 alone, 302 million cows, 656 million turkeys, 1.48 billion pigs, and a gob-smacking 68 billion chickens were <a href="https://ourworldindata.org/grapher/animals-slaughtered-for-meat" target="_blank" rel="noopener noreferrer">slaughtered for meat worldwide</a>. And those figures do not include chickens killed in dairy or egg production.</p><p>If brought to scale and widely available, clean meats could become serious competitors to traditional meat. <a href="https://bigthink.com/technology-innovation/meat-alternatives" target="_self">One report has even predicted</a> that 60 percent of the meat people eat by 2040 won't come from slaughtered animals. It could be just the thing for people looking for a meat substitute but who find tofurkey as distasteful as, well tofurkey.</p>