Brendan Hoffman / Getty
- Recent studies showed volunteers lost equal or more weight on high-carb, calorie-restricted diets than low-carb, calorie restricted diets.
- There might be positive benefits to short-term usage of a ketogenic diet.
- One dietician warns that the ketogenic diet could put diabetics at risk for diabetic ketoacidosis.
A few weeks ago I stopped by the Korean stand at my local farmer's market. I was picking up fermented daikon and tempeh when the seller tells me about a woman that had just stopped by to ask if tempeh has protein. The look on my face answered his non-question. He continues to tell me that she's on a "no protein" diet because, well, at this point, I just give up.
Humans can be absurd in our dietary beliefs. Every other animal eats due to necessity and availability. Our relative luxury has afforded us the opportunity to partake in eating plans that thwart basic biological needs. Some plans seem to make sense until science steps in.
For a minute it appeared the keto diet had traction. Advocates were seeing drastic weight loss. By their telling, "Big Food" is waging a longtime conspiracy to inject as many big carbs into our bodies as possible. (Not that excess carbohydrates, especially in the form of sugar, isn't a problem.) My personal experience with keto, which lasted roughly three months, was successful in certain regards. Weight loss wasn't the intended goal, though that did happen; I did it to address chronic GI issues.
As it turns out, I might have inadvertently nailed the timing, at least according to one doctor that never puts his clients into ketosis for more than three months. Let's face it: our ancestors never purposefully restricted carbohydrate intake. They just didn't have a Whole Foods to shop at. Macronutrients weren't on their minds as they had no awareness of the building blocks of calories to begin with. The question was never "What's my meal plan this week?" but rather, "What can I catch today? What plant is ripe to forage?"
Now that more research is emerging, the news on keto isn't good. Scientists leading one 2016 study, led by National Institutes of Health obesity researcher Kevin Hall, confined 17 volunteers to a hospital for a two-month stay. This is important, as self-reported studies are always at risk of being invalidated by faulty data. In this study, volunteers ate plenty of sugary carbs for the first month; during the second they received the same caloric load, replacing the bulk of those carbs with fats.
Vox Media
At the end of the two months, Hall was unimpressed.
In this case, we saw daily insulin secretion drop substantially within the first week and stay at a low level. But we only saw a small transient increase in energy expenditure during the first couple of weeks of the [low-carb] diet, and that essentially vanished by the end of the study.
Despite what some expected, it took the volunteers on the high-fat diet 28 days to lose as much weight as those on the baseline diet lost in 15 days. (All volunteers were overweight; the mechanism for their weight loss was lower daily caloric intake.) To be fair, there was no control group and calorie restriction generally has a bigger impact during the first month on any diet. That said, this study provided a serious blow to low-carb advocates.
As dietician Bonnie Taub-Dix told Well + Good, there should be an emphasis on eating the right carbs, such as whole grains. She's also not a fan of diabetics getting into ketosis, even though this community is specifically targeted by advocates. "It can cause DKA, diabetic ketoacidosis," she said. "This happens when your body is producing a lot of ketones and can lead to vomiting, diarrhea, feeling faint, and being [excessively] thirsty."
Yagi Studio / Getty Images
The Internet is filled with anecdotal tales of triumph thanks to ketosis. The diet should not be completely written off, as other studies — on mice — have shown positive benefits, such as weight loss and memory improvement. Again, these are short-term fixes, not longitudinal proof.
Besides, a 2018 study, published in JAMA, found that low-carb and low-fat diets were equally effective for weight loss. This isn't the only evidence of this fact. A 2015 meta-analysis found that low-carb diets barely outperformed low-fat diets.
As Taub-Dix notes, balanced dieting is "boring." People always want the next great thing, be it a shamanically-blessed Amazonian berry or a supercharged Pacific Northwestern mushroom. I recently had dinner with a fellow who talked about his nootropics regimen, which greatly increases his focus, yet he checked his cell phone every five minutes during our two-hour meal. The distance between our brain and our gut remains too long to traverse.
--
From Your Site Articles
Related Articles Around the Web
Image Point Fr / Shutterstock
Mind & Brain
- Researchers have found that some basic words appear to be more memorable than others.
- Some faces are also easier to commit to memory.
- Scientists suggest that these words serve as semantic bridges when the brain is searching for a memory.
Cognitive psychologist Weizhen Xie (Zane) of the NIH's National Institute of Neurological Disorders and Stroke (NINDS) works with people who have intractable epilepsy, a form of the disorder that can't be controlled with medications. During research into the brain activity of patients, he and his colleagues discovered something odd about human memory: It appears that certain basic words are consistently more memorable than other basic words.
The research is published in Nature Human Behaviour.
An odd find
Image source: Tsekhmister/Shutterstock
Xie's team was re-analyzing memory tests of 30 epilepsy patients undertaken by Kareem Zaghloul of NINDS.
"Our goal is to find and eliminate the source of these harmful and debilitating seizures," Zaghloul said. "The monitoring period also provides a rare opportunity to record the neural activity that controls other parts of our lives. With the help of these patient volunteers we have been able to uncover some of the blueprints behind our memories."
Specifically, the participants were shown word pairs, such as "hand" and "apple." To better understand how the brain might remember such pairings, after a brief interval, participants were supplied one of the two words and asked to recall the other. Of the 300 words used in the tests, five of them proved to be five times more likely to be recalled: pig, tank, doll, pond, and door.
The scientists were perplexed that these words were so much more memorable than words like "cat," "street," "stair," "couch," and "cloud."
Intrigued, the researchers looked at a second data source from a word test taken by 2,623 healthy individuals via Amazon's Mechanical Turk and found essentially the same thing.
"We saw that some things — in this case, words — may be inherently easier for our brains to recall than others," Zaghloul said. That the Mechanical Turk results were so similar may "provide the strongest evidence to date that what we discovered about how the brain controls memory in this set of patients may also be true for people outside of the study."
Why understanding memory matters
Image source: Orawan Pattarawimonchai/Shutterstock
"Our memories play a fundamental role in who we are and how our brains work," Xie said. "However, one of the biggest challenges of studying memory is that people often remember the same things in different ways, making it difficult for researchers to compare people's performances on memory tests." He added that the search for some kind of unified theory of memory has been going on for over a century.
If a comprehensive understanding of the way memory works can be developed, the researchers say that "we can predict what people should remember in advance and understand how our brains do this, then we might be able to develop better ways to evaluate someone's overall brain health."
Party chat
Image source: joob_in/Shutterstock
Xie's interest in this was piqued during a conversation with Wilma Bainbridge of University of Chicago at a Christmas party a couple of years ago. Bainbridge was, at the time, wrapping up a study of 1,000 volunteers that suggested certain faces are universally more memorable than others.
Bainbridge recalls, "Our exciting finding is that there are some images of people or places that are inherently memorable for all people, even though we have each seen different things in our lives. And if image memorability is so powerful, this means we can know in advance what people are likely to remember or forget."
Temporal lobes
Image source: Anatomography/Wikimedia
At first, the scientists suspected that the memorable words and faces were simply recalled more frequently and were thus easier to recall. They envisioned them as being akin to "highly trafficked spots connected to smaller spots representing the less memorable words." They developed a modeling program based on word frequencies found in books, new articles, and Wikipedia pages. Unfortunately, the model was unable to predict or duplicate the results they saw in their clinical experiments.
Eventually, the researchers came to suspect that the memorability of certain words was linked to the frequency with which the brain used them as semantic links between other memories, making them often-visited hubs in individuals's memory networks, and therefore places the brain jumped to early and often when retrieving memories. This idea was supported by observed activity in participants' anterior temporal lobe, a language center.
In epilepsy patients, these words were so frequently recalled that subjects often shouted them out even when they were incorrect responses to word-pair inquiries.
Seek, find
Modern search engines no longer simply look for raw words when resolving an inquiry: They also look for semantic — contextual and meaning — connections so that the results they present may better anticipate what it is you're looking for. Xie suggests something similar may be happening in the brain: "You know when you type words into a search engine, and it shows you a list of highly relevant guesses? It feels like the search engine is reading your mind. Well, our results suggest that the brains of the subjects in this study did something similar when they tried to recall a paired word, and we think that this may happen when we remember many of our past experiences."
He also notes that it may one day be possible to leverage individuals' apparently wired-in knowledge of their language as a fixed point against which to assess the health of their memory and brain.
