Health & Long-term Keto Diet

by Stephanie

My fitness group ladies keep coming back to discussing the new diet fad of keeping your body always in a state of ketosis.  Just today (note: this was a couple of weeks ago) we looked at an article that is again… not very favorable.  And after reading it, I’m definitely beginning to see why these fads can be so annoying to fitness instructors and nutritionists.

When I first heard about the keto diet, I immediately remembered studying case studies of diabetic people in ketoacidosis in college, and was alarmed that there were apparently women who were trying to get their bodies into that state of chemical toxicity in producing ketones in their blood.  BUT those two things are different.  Ketoacidosis is a very high level of ketones, whereas ketosis is just the presence of ketones.  It’s similar, but one is life-threatening, while the other seems benign.

My fitness ladies are skeptical, quite a few have tried it and already been badly burned, having experiences that ranged from physical illnesses and side effects like kidney stones, to higher cholesterol levels that forced them to have to go back to a normal, much healthier diet.

This article delves into those issues from a scientific perspective which is nice.  My background was biology and chemistry… and very heavy on biochemistry – how those two work inside your body – so the science stuff speaks to me.


From an obesity researcher quoted in the article:

“But just as other “don’t eat this” or “eat more of that” diets of the past didn’t cure all, so goes the ketogenic diet. “It’s one of these diets where so many people are talking about losing tons of weight, improving their health risks, beating cancer, and all these other lofty claims,” says Stephan Guyenet, an obesity researcher and author of The Hungry Brain. “But all those big claims are far ahead of the current scientific evidence.”

It does work… reading the awesome stories on reddit are incredibly inspiring!  But again, it’s part common sense (following your macros), part fad (eating 90% fat!), and part diet (lowering caloric intake by not eating carbs, which are the bulk of calories per day we normally eat anyway).

The main benefit I saw while I was trying it myself for curiosity, is that if you’re eating crap foods, processed sugars and bad carbs, it at least teaches you those things are bad for weight loss (and overall health).

It also teaches men and women who had poor diets and lazy habits to include a TON more veggies and green leafy fiberous foods into their diet – which of course will aid in fat loss and curb hunger.

Like I said, a lot of it is just common sense, and the main part is restricting caloric intake (which always leads to fat loss, no matter what diet you’re on).

It’s the perfect diet for very overweight men or women who have no idea where to start.

More on that from this article:

“Keto doesn’t seem to be any better for weight loss compared to any other “diet,” Kashey says. And that’s due to how weight loss science works. “People get excited about the idea that the ketogenic diet burns fat stored on your body,” Kashey says. “Yes, ketones can be made from your stored fat, but ketogenic diets are high in fat. Therefore, the fat you eat is what gets converted to ketones. How do you make sure you are burning more fat than you are eating? You eat less fat. That sounds an awful lot like reducing calories.””

For women, it can be a little dangerous as it messes with our hormone production, which affects bone loss longterm. (From article):

“But it may also have some health-based drawbacks, Scott-Dixon says. “Especially in women, it can disrupt hormonal production,” she says. “You also sometimes see immunity issues and nutritional deficiencies, so you’re maybe risking getting sick, and becoming malnourished, which is sort of embarrassing if you live America.” Guyenet agrees, saying “few human groups have ever lived in chronic ketosis, so I’m skeptical that it’s a good idea.””

I’ve read from a lot of the Keto Gurus that human groups have been mostly living in ketosis throughout history.  It’s something you’d have to look into for yourself, but I personally think just following a healthy, well-balanced diet (by which I mean including carbs), is probably the best way to go, especially (as I found out personally) if you enjoy exercise or sports and do endurance or high intensity workouts.

The Keto Diet seems to scientifically harm your overall athletic performance and long-term energy.  So if you do aerobics or are a die-hard runner, the longer you’re in ketosis, you’ll be worsening at your beloved sport or hobby:

“One study of endurance athletes found the diet led to performance declines, and another found that it hurt endurance race performance. One study on mountain bikers, however, did show some promise. Any benefits of exercising in ketosis are likely offset by the drawbacks, covered here. “You know what has been proven to improve exercise performance, though?,” Kashey asks. “Carbs.””

Coming from a long-time runner and dancer, it is very hard to imagine exercising at your best level (much less racing like one study found) without the necessary carbs that fuel long-term endurance.  I thought all that was common sense, even as a teenager when our coach was explaining it to us.

The Keto Gurus (who when I researched more on their actual diet, were eating more protein than they should be to be in ketosis, and carb-fueling on days they called “Re-Feed” days, lol), will try to tell you that being in ketosis produces more ATP energy during your workouts.  It’s just not true scientifically.  The body cannot break down fat as fast and efficient as carbs when using them for high intensity workouts or in weight lifting (in order to build muscle), so while 1 gram of fat does in theory produce more ATP eventually, it’s not fast enough or easy enough for the body to do this under exercise stress.

I found a good scientific article explaining what I was feeling in my workouts when being in a constant state of ketosis.  This study that was done was involving different sets of mice, one set that was prone to epileptic seizures, and another that was normal and the control (no physical abnormalities).  The sets of mice were all put on a ketogenic diet to model the human version of the diet.  The mice prone to epilepsy, when on a ketogenic diet, were significally improved in their health and also surprisingly made “normal” amounts of ATP energy that they weren’t previously able to make (so they were under-making ATP on regular diets – whereas the keto diet helped them to be at normal ATP production).  It didn’t make them make “more” than what is normal, but it did help them make more than they used to on regular diets that weren’t working for them health-wise.

The normal mice however, who didn’t have seizure and health problems, when measured actually produced significantly less ATP-energy than what they had been producing when they were allowed to eat carbohydrates.  (

So if you have medical conditions like epilepsy, being on the keto diet has been proven to possibly help restore you to normal levels of ATP production, greatly impacting your life in positive ways.  However, if you’re the typical adult without epilepsy, your ATP levels may be “significantly decreased,” on this diet due to the lack of healthy carbs.

It’s actually because of that, heavy weight lifting is not doable on keto – they actually advise against it.  Mostly because you’re not eating enough carbs in order to build and rebuild muscle!

“Therapeutic use of ketogenic diets should not require constraint of most forms of physical labor or recreational activity, with the one caveat that anaerobic (ie, weight lifting or sprint) performance is limited by the low muscle glycogen levels induced by a ketogenic diet, and this would strongly discourage its use under most conditions of competitive athletics.”

(From here:

Here are some hardcore cyclists talking about their negative experiences in exercise performance on keto:

Depending on how hard you work out and how much ATP you need, it may affect your workout and training to a greater degree.

Just as a recent, personal experience I had the other day (already quite a few days in to ketosis), I was working out very hard on the stairmaster at our gym with my husband.  After only doing 15 minutes of that exercise, which was intense intervals of fast and furious climbing against increased resistance levels (large steps), and slow climbing to a lighter resistance, I had to stop and afterward, felt like I was going to black out.  LOL it was NOT cool!

After researching my experience with doing HIIT (intervals of high intensity followed by lower intensity), it turns out “dizziness” and low blood sugar (leading to blacking out) is one of the side effects of this diet.  Grrreeeaaat. Try feeling dizzy when you’re doing an intense cardio workout up high on a stair master!  Oh wait!!  You can’t because you may fall off and break something!  lol

Negative side effects of the Keto Diet:

  • Low blood sugar (bad for me… I already lean toward low blood sugar… this could be why I almost blacked out after only 15 minutes of intervals on the stairmaster)
  • Messed up electrolytes and minerals – you have to be on top of taking extra magnesium and salt daily to counteract your regular loss of electrolytes
  • Heart palpitations – because of the messed up electrolyte (salt and water) balance in your blood, again it can be remedied, but if you are prone to heart problems in your family, this could cause issues long-term and you’d have to be VERY on top of checking your blood levels
  • Muscle Cramps – again because of messed up electrolyte balances
  • Sleep problems – due to lower insulin levels and less serotonin production (causing anxiety at night).  A trick keto-gurus do to combat this is to (surprise!) eat a tiny bit of carbs at night so they can sleep better.
  • If you’re a woman, it will mess with your menstrual cycle hormones, possibly even making you not have a period (amenorrhea), which is known to cause bone loss long-term (and is generally a side effect of anorexia as well)

I guess it’s just human nature to look for a magic formula or easy route to get healthy, but it seems a little more complicated than what cutting out an entire food group (long-term) can do.  Does the Keto Diet have pros?  Yes.  Does it work?  Yes, you can check out all the success stories on reddit to see for yourself!  It’s honestly the perfect intro diet for very overweight people who aren’t exercising normally and eating loads of bad carbs in their diet.  It weans them off of the bad carbs, gets them eating a TON more veggies and leafy greens they should be eating anyway, and really does help them lose fat due to these habit changes.


But is it a little dangerous in how it paints carbs as the “Bad Guys” for optimal health?  Yea… and with all my training and experience in sports and athletics, I can see how this diet would be annoying to fitness instructors or coaches who understand how much protein their athletes need, along with carbohydrates for maximum performance.


You won’t find any Olympic Athletes on the Keto diet, and if they are, they’re definitely incorporating carbs on “Re-Feed” or re-fuel days on the weekends to compensate.  But with the protein restrictions to be in ketosis, I highly doubt any Olympians are on it, and definitely not long-term.


Ultimately you have to do what’s best for you long-term and do what you can realistically stick to.  There’s no way I’d be willing to give up my high intensity workouts and weight-lifting to build muscle to lose fat on this diet, when I’m already able to lose fat (and train like an athlete) on a healthier diet including carbs I love.


But if you can stick to it, and you’re willing to brave the negative side effects and messing with your feminine hormone production, then go for it.  To me that’s too much fuss to be tracking electrolyte balance and ketone production in my urine everyday, and part of overall fitness is keeping your mind at peace and relaxed and less stressed out (which being worried about not messing up my electrolyte balance, or if I’m messing up my period and bone density, would stress me out).


This blog is dedicated to approaching fitness for lifelong benefits and in a positive, relaxing way.  I want people to be aware how easy being fit really is once you have the knowledge and power to act on it, and make changes in your life.  There’s no need to pee on pH sticks everyday or track ketones in your blood.  There’s no need to stop eating carbs or a healthy amount of protein in order to build muscle.  In my opinion, any diet that cuts out an entire food group for the rest of your life, is just not peaceful or easy to do longterm.