Objective perspectives on keto?

February 1, 2020 5:06 PM

I adopted a very low carb, higher fat diet in the new year to help lose fat. So far, I've been successful in terms of weight loss. But, I do have some questions about long-term outcomes and impacts of this way of eating. Is there anything I can read that is accessible, and actually approaches this from an objective perspective?

Basically, I've been eating lower carb--usually around 30-35 net carbs on average—and higher fat. My macronutrient ratios hover around 10% carbs, 60% fat, 30% protein, and I eat around 1800 calories a day. What carbs I do get are almost entirely from vegetables, which I eat a lot more of than I used to. I still have the odd cookie; I've also had pizza a couple of times and had nachos while out with a friend once and handled it fine. I don't think I'm actually in ketosis.

So far, this way of eating has been good for me. I've lost 20 lbs (I'm sure a good bit of it post-holiday water weight, but still!) and don't feel like I'm starving or anything like that, while still being able to maintain a good activity level (weights and some cardio about 4x a week). The food I'm making tastes good, and, so far, I haven't felt the urge to binge like I sometimes have on the last while eating lower calorie diets.

However, I've heard strongly conflicting opinions about keto. A dietitian I've spoken to said that it is almost certainly unsustainable (and maybe it is?) as well as unhealthy due to the fat, for instance, which makes sense from a commonsense perspective? But I've also read things by medical professionals (i.e. Jason Fung) saying it's a perfectly cromulent diet, and that the lower fat diets that are the norm actually contribute more to obesity and other related health outcomes than the higher fat diet might. The issue I have is that a lot of the pro-keto stuff tends to be... conspiratorial, I guess? and I've read that the work of some of the figures that keto folks often point to (like Gary Taubes) isn't all that scientifically rigorous, and/or misconstrues research findings.

I know nutrition science is insanely complex, but is there anywhere I can go that can provide a somewhat balanced view of things?

posted by synecdoche to Health & Fitness (14 answers total)

Should you try the keto diet? (Harvard Health Letter, Dec. 12, 2019)

"The keto diet is primarily used to help reduce the frequency of epileptic seizures in children. 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," warns registered dietitian Kathy McManus, director of the Department of Nutrition at Harvard-affiliated Brigham and Women's Hospital. [...]

The popular low-carb diets (such as Atkins or Paleo) modify a true keto diet. But they come with the same risks if you overdo it on fats and proteins and lay off the carbs. So why do people follow the diets? "They're everywhere, and people hear anecdotally that they work," McManus says. Theories about short-term low-carb diet success include lower appetite because fat burns slower than carbs. "But again, we don't know about the long term," she says. "And eating a restrictive diet, no matter what the plan, is difficult to sustain. Once you resume a normal diet, the weight will likely return."

Disclaimer: As a service to our readers, Harvard Health Publishing provides access to our library of archived content. Please note the date of last review on all articles. No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.

Ketogenic diet: Is the ultimate low-carb diet good for you? (Marcelo Campos, MD, Harvard Health Blog, Jul. 27, 2017)

It is also important to remember that “yo-yo diets” that lead to rapid weight loss fluctuation are associated with increased mortality. Instead of engaging in the next popular diet that would last only a few weeks to months (for most people that includes a ketogenic diet), try to embrace change that is sustainable over the long term. A balanced, unprocessed diet, rich in very colorful fruits and vegetables, lean meats, fish, whole grains, nuts, seeds, olive oil, and lots of water seems to have the best evidence for a long, healthier, vibrant life.

posted by katra at 6:26 PM on February 1, 2020 [4 favorites]

Read "The Art and Science of Low Carbohydrate Living" by co-authors Jeff S. Volek, PhD, RD (registered dietician) and Stephen D. Phinney, MD, PhD (medical doctor). They go in depth into the science behind why and how a very low carbohydrate/higher fat diet works. They have also co-authored "The Art and Science of Low Carbohydrate Performance", which adds further research and information to the original book, and explains why and how a person who is able to function in ketosis will outperform those who is not accustomed to exertion without a constant stream of carbohydrates in the system.
posted by itsflyable at 6:31 PM on February 1, 2020 [4 favorites]

Here's a bunch of papers on saturated fat.
posted by MillMan at 6:33 PM on February 1, 2020 [1 favorite]

What Is the Keto Diet and Does It Work? (NYT, Jan. 2, 2020 / reprint)

If you want guidance, it’s recommended you consult with a registered dietitian. [...] For the first two to six months, there’s evidence that a very low-carbohydrate diet can help you lose more weight than the standard high-carbohydrate, low-fat diet, according to a new literature review of low-carb diets by the National Lipid Association.

“By 12 months, that advantage is essentially gone,” said Carol F. Kirkpatrick, director of Idaho State University’s Wellness Center, and lead author of the new literature review. After that, weight loss seems to equalize between those two popular diet regimens. She said keto was best used to kick-start a diet, before transitioning to a carb intake that you can adhere to for the longer term. [...]

The keto diet appears to deliver fast results: The first pounds may seem to slip off. That can be seductive but it’s likely water weight. Then, dietitians say, it’s back to energy in minus energy out. You can absolutely gain weight on any diet if you’re consuming 5,000 calories a day, according to Dr. Linsenmeyer, who is also director of Saint Louis University’s Didactic Program in Dietetics. “It’s not like it is going to magically alter your metabolism to where calories don’t matter anymore,” she said. And when resuming the carbs, that water weight returns. [...]

Whichever eating plan one chooses for 2020, Dr. Hall said certain recommendations are nearly universal: cut down on refined carbs and ultra-processed foods, and consume more whole foods, particularly non-starchy vegetables, such as broccoli, asparagus and spinach.

posted by katra at 9:51 PM on February 1, 2020

I found this video to be unclouded by the misapprehensions that typically creep in when people discuss keto diets.

It features Stanford researchers, Dr. Lucia Aronica Ph.D. and Dr. Shebani Sethi Dalai MD, who discuss the promises, perils, and practical clinical aspects of ketogenic diets and intermittent fasting.

I’m looking forward to Dr. Aronica’s results on personalized diets.

My husband has been doing a keto diet for 3+ years. He’s thriving in it. He did a lot of reading and said pretty much what’s in the video. If you’re interested, memail me and I’ll ask for his reading list.

It’s not practical for me at this point in my life, but I’d otherwise follow a keto diet without qualms of any kind.
posted by rw at 10:38 PM on February 1, 2020 [1 favorite]

Here’s a study in The Lancet about the links between carbohydrate intake and mortality that uses patient data going back decades, it’s pretty accessible and is a good jumping off point to the research that’s out there.

You might also be interested in the robust research out there showing that regardless of method, we don’t have a reliable way to change our weight long-term any meaningful way, but we do see plenty of health benefits regardless of weight changes when we change behaviors. Because the diet industry is a $65 billion/year one it’s pretty easy to miss that anyone selling you on diets is making money on repeat customers since it’s virtually guaranteed they’ll fail, there’s a lot of money to be had in selling folks on keto and low-carb since the weight loss can happen quickly. Unfortunately the weight cycling that happens when the weight comes back has long term health effects worth taking very seriously.
posted by the thorn bushes have roses at 12:14 AM on February 2, 2020 [3 favorites]

I've been on keto for two and a half years, and my bloodwork this autumn was all excellent. As for "unsustainable" - I'm not sure what that means. Some people have trouble sticking to the diet because carbs can have an addictive quality and it's hard not to eat them. But I've sustained this way of eating for 2.5 years and feel great. I eat lots of above-ground vegetables, lots of cheese and other high-fat dairy, lots of nuts, some meat. In a pinch, I can eat fast food (e.g. a burger with no bun), which is handy if I don't have kitchen access.

I'm curious about the long-term effects of keto, and I'm especially interested in gut microbiota. I haven't seem much definitive stuff on that, and if worrying research came out, I'd take it seriously. I'd want studies looking at high-fat consumption in the absence of simple carbs (the combination of fat and carbs seems pretty clearly to produce negative health outcomes, and many nutritional studies involving "high fat" also feed rats high levels of carbs as well). I would be much less interested in what a nutritionist has to say. They seem very biased towards "balanced" diets, higher-carb intakes, etc. (My dad has a highish-moderate A1C and was, under my advice, lowering his carb intake and had ceased eating dessert, and a nutritionist recently told him that as long as he keeps his fat intake moderate, it's not harmful for him to eat sugar "in moderation, every day" - ???) It's also possible that different people do better on different diets, possibly based on genetics and/or the gut microbiome.

Also, I'd distinguish between keto and low carb. Benefits of both diets do overlap, but ketosis may well provide distinct outcomes. I've read things about ketones in the body specifically (anti-inflammatory etc.). You're either in ketosis or you're not. If you're not, you'd be better looking into effects low-carb diets rather than keto.
posted by ClaireBear at 7:56 AM on February 2, 2020 [2 favorites]

Interesting papers are posted here, with discussion. Obviously not the most objective community, but they are genuinely interested in the nutritional outcomes.
posted by ClaireBear at 7:58 AM on February 2, 2020

Perhaps more detailed than you're looking for, but I thought this was an interesting (albeit depressing) run-through of some research on diet - especially the idea of why various different diets (vegan, keto, etc.) all seem to work.
posted by ClaireBear at 8:00 AM on February 2, 2020

I've been eating more or less keto for the past several years. My doc is thrilled that I lost a lot of weight and have kept it off, and my labs are all terrific. So far so good. I recently turned 50, I just started CrossFit, I'm feeling great and I'm quite habituated to stay at less than 20 net grams carbs/day.

That's an anecdote, and the following is not a peer-reviewed observation or anything. I do have a PhD in biochemistry, which might count for something. My take on it is: bodies are clearly designed to run on fat, because that's the primary way bodies store fuel. (The body can store a little bit of carbohydrate, in liver and muscle, but clearly the way we are designed to store excess calories is as fat.) I also note that, although humans need to have a blood glucose concentration within a certain, tightly regulated range, there is no nutritional need to eat carbohydrates. I repeat, there is no such thing as a nutritionally essential carbohydrate. Normal human metabolism can make the (many, diverse) sugars it needs from other dietary components, just as it makes a thousand other biomolecules, so there is no need for exogenous carbohydrates.

Last thought: we are in the golden age of genomics, and science's understanding of individual variation is expanding exponentially. The era one-size-fits-all nutritional advice is essentially gone and sometime in the not very distant future there will be clinical biomarkers to steer people to better food choices for their own unique metabolisms. In the meantime, we have trial and error. If it works for you, keep at it.
posted by Sublimity at 5:40 PM on February 2, 2020 [8 favorites]

I've been on keto for two and a half years...I would be much less interested in what a nutritionist has to say...

I've been eating more or less keto for the past several years...That's an anecdote, and the following is not a peer-reviewed observation or anything...My take on it is...

These are not objective perspectives.
posted by some little punk in a rocket at 11:37 PM on February 2, 2020 [2 favorites]

These are not objective perspectives. Yep, as stated upfront. There isn’t a huge body of long term studies to call on. Well, in Good Calories, Bad Calories Taubes includes historical epidemiology information to make his case, but the OP seems skeptical of him from the outset, so whatcha gonna do?

The two points I made—that fat is how fuel is stored in human bodies (so we must be designed to metabolize fat as fuel) and that there is zero evidence that carbohydrates are nutritionally essential—are not opinion, and they are not controversial in biomedical understanding. I bring them up because I’ve been following the biomedical discussion with interest in the past few years, and I’m surprised that these two key points are almost never explicitly stated/considered.
posted by Sublimity at 6:10 AM on February 3, 2020 [1 favorite]

May I suggest watching this first:

https://gamechangersmovie.com
posted by Everyone Expects The Spanish Influenza at 2:05 PM on February 18, 2020

The Summary of the Abstract from the Lancet study is interesting:

"Both high and low percentages of carbohydrate diets were associated with increased mortality, with minimal risk observed at 50–55% carbohydrate intake. Low carbohydrate dietary patterns favouring animal-derived protein and fat sources, from sources such as lamb, beef, pork, and chicken, were associated with higher mortality, whereas those that favoured plant-derived protein and fat intake, from sources such as vegetables, nuts, peanut butter, and whole-grain breads, were associated with lower mortality, suggesting that the source of food notably modifies the association between carbohydrate intake and mortality."
posted by Everyone Expects The Spanish Influenza at 2:09 PM on February 18, 2020