Is A Low-Carb Diet Effective For Burning Fat? Is Ketosis Dangerous?

“The future is already here – it’s just not evenly distributed.”
~William Gibson

One hundred years from now, medical doctors, scientists, nutritionists, and the general public will be puzzled and astounded by how few of us were able to grasp the obvious – high-carb, low-fat diets simply do not achieve long-term fat loss.

Athletes, bodybuilders, Hollywood and others have known for decades that a low-carb, high-protein diet achieves incredible fat metabolism and enables rapid muscle gains. Hundreds of scientific studies have – again and again – proven the same. Special interests have ridiculed and disparaged these approaches and prevented most of this knowledge, however, from being incorporated into conventional wisdom.

While some diets do follow effective fat loss principles, many take them to extremes (Atkins, Dukan, the Ketogenic Diet, etc.), advocating weight loss at any cost. Avoiding fruits and vegetables while encouraging hot dogs and bacon binges – while it might actually help you lose weight in the short term – is not a healthy or sustainable strategy. The LeanBody System is unlike these diets in that you will achieve fat loss and muscle gains as a direct result of improving your overall health, not sacrificing it.

So How Do Low-Carb Diets Work?

Extreme low-carb diets push the body into ketosis, which means that the body primarily burns fat (instead of carbs) for energy and levels of ketones in the blood are elevated. Ketones are small carbon fragments created by the breakdown of fat stores after the body is depleted of stored glucose (known as glycogen). Humans can use ketones as energy for bodily functions and even as a replacement for glucose to provide fuel to the brain.

Since the body relies on stored fat for energy, people lose weight – usually rapidly – while in ketosis. However, since ketones are toxic in excess, the body actively attempts to rid itself of them. Ketones are expelled from the body in the urine and through the lungs, causing a sweet and slightly foul-smelling breath.

How Long Does It Take to Reach Ketosis?

Under 50 grams of carbs a day will eventually get you to ketosis. Depending on the person and level of activity, it could take 2-3 days or up to a week before the body’s glycogen is depleted.

Is Ketosis Dangerous?

The ketogenic diet often has short term side effects including dehydration, constipation, and occasionally kidney stones or gall stones. Very high ketone levels can be toxic, making the blood more acidic which can damage the kidneys and liver. However, ketoacidosis is quite different than ketosis, with the former generally occurring as a result of a medical condition. But – if you do it right and eat high-quality, nutrient dense foods – ketosis can be generally safe for the disciplined dieter.

Is Ketosis Abnormal?

Historically, there is evidence that some populations have experienced ketosis without serious damage to health or longevity. Some native humans seemingly thrived while in seasonal or extended states of ketosis. However, it must be assumed that these populations did not choose a state of ketosis; rather, they experienced ketosis as a result of fruits and vegetables being unavailable for periods of time in their environment.

Some people tend to tolerate ketosis better than others. Although some of my clients have struggled with workouts and mental clarity when they first reach ketosis, most folks stabilize after a week or two eating high-fat, low-carb.

Yes, ketosis is a state that the body can tolerate. It undeniably leads to weight loss and even has been used as a treatment for epilepsy since the turn of the century. It’s getting to ketosis, however, that presents the struggle. I feel sluggish, cranky, and generally down on life. This stabilizes after a few days. In short, Ketosis is not a condition I enjoy for extended periods of time, but its benefits for fat loss are undeniable.

The Cyclical Ketogenic Diet for Bodybuilding and Extreme Fat Loss

The cyclical ketogenic diet is often used by competitive bodybuilders to achieve spectacularly low body fat (well, that and buckets of drugs). However, due to its strict non-allowance of carbs throughout the week (and I mean none – not even a carrot), it is next to impossible to eat enough micronutrients for your body to function optimally. It’s incredibly effective for cutting fat, but generally not an attractive lifestyle choice for the Average Jane or Joe.

So What is The Verdict?

It’s not rocket science. Excess carbs make you fat. Once you accept that fact, you can control carb intake depending on your level of activity to achieve optimal energy levels and fat metabolism.

Dipping into occasional short-term ketosis may not be a serious health risk and may even provide some benefits… But I do not advocate extended periods of ketosis for most of my clients. Can you make it work? Yes. But it’s pretty advanced stuff.

Consuming some carbs is easier on the body than consuming zero carbs or lots of carbs. The optimal level of carb intake for healthy fat loss is between 75-150 carbs a day depending on your activity level.

Don’t obsess yourself with avoiding vegetables and urinating on keto-sticks; occupy your mind with the thought of nourishing your body with healthy food. Regardless of whether or not you stray into ketosis, in a healthy and well-nourished body, fat loss is effortless and automatic.

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  1. You’re totally right! I went low-carb and that was the only thing that helped me lose weight! I couldn’t believe how easy it was at first. But then after not eating any vegetables I felt sick. Once I started eating them again, I felt better but the weight didn’t come back!

  2. First man, I love your site. Ya I tried the ketogenic diet when I was training for my photo shoot and I felt sick after a while. I couldn’t get through my workouts. But I’ll try it again with carb loading on the weekend. That makes sense.

  3. Love the site! Been reading it all evening and I like your ideas (and how you write… I kinda suck a writing.. haha). The one thing on this article I’m not crazy about is saying Atkins promotes binges with bacon & bologna. I always thought that too, since that’s what goes around word of mouth and you hear on TV, etc. After getting into primal & lowcarb from Marks Daily Apple, I decided to grab the newly written Atkins book from 2011 (?) to see exactly what it was all about (It may have been from 2010 now that I think of it… recent either way).

    I was pleasantly surprised to see that it doesn’t promote that it all. It does have you do a 2 week ~20g carbs phase … and then it shows you how to increase your personal carb level to fit your needs. Their sweet spot is around 50 – 100+ g/carbs once you’ve got things under control. Very paleo/primal-like.

    They recommend eating higher quality proteins, a foundation of vegetables, enough fat to satisfy at each meal but not crazy amounts like I thought they would, & even some fruit if it works with you. Very primal if you ask me. (Example breakfast: cook 2-3 eggs in 1T butter with sauteed spinach & onions, & maybe a couple slices of bacon or avocado if you want.) They made sure to ward off the Atkins “reputation” by saying that you need to eat just enough protein/veggies/fat to satisfy, but not stuff yourself like everyone thinks/says.

    It does mention both bacon & bologna … you can eat some bacon if you want, but unprocessed meats are better … and avoid crap foods like bologna, etc. There’s also mention of things like cream, butter, coconut oil, olive oil, nuts, etc

    I was really surprised, but happy, to see what all they really recommend, which was a far cry from “what I’ve heard” about it.

    The guys that wrote it are big time low carb researchers and are definitely not pushing unlimited amounts of crap foods like bologna. One of the guys, Dr. Jeff Volek has a pretty serious 6-Pack too along with awesome low carb studies going on.

    There is mention of Atkins products (because Atkins is a company and not just Dr. Robert anymore)… but they were reluctant to include them. They made sure to note several times that they’re not needed whatsoever and mentioned it in several interviews after writing the book. They just weren’t into the idea of promoting those kinds of things, but had too since they were asked by the Atkins company to write the book based on all their collective research.

    Anyway, I just thought I’d mention that since I thought the same thing until I checked out the book myself. It’s worth a look just to see what all they say yourself. I bet most people would be surprised by what they have in it.

    • Thanks Kevin! You’re absolutely right: the *real* Atkins doesn’t encourage binging on processed food (although I do take issue with their packaged foods and bars – they’re low on carbs but heavy on chemicals). I actually talked to Jimmy Moore a bit about this recently – people have the wrong idea about what Atkins and low-carb means. I was very surprised as well (quite happily, I might add) when I read the original book and found a much more balanced approach from Atkins than what you’d expect. Word of mouth usually isn’t the whole truth!

      • You say this now, as you have been confronted with the truth of what “Atkins diet” is really about, but on your site, which is wwhere most people get their info, you scorn his advice, which by the way is for metabolically challenged people. Put it right, don’t put good advice down just to sell your book>

  4. I’ve used this diet a good portion of my adult life tending to eat sirloin steak & fish exclusively w/water to drink going absolute 0 carb on 4 week intervals inducing ketosis quickly. Perhaps my constitution is different from others but I don’t tend to suffer the symptoms others complain of, IE lethargy, lack of focus etc. I find large quantities of water, up to 96 oz a day helps my kidneys push the protein.

    • Awesome! I’m actually training a bodybuilder to do a ketogenic Paleo diet to slim down right now. It was rough for him to make the shift at the beginning, but he’s rocking it now. Glad you have good results with keto!

  5. Crazy Atkins Girl says:

    And just where in any of the Atkins publications does Atkins recommend binge eating bacon and bologna? No where! He says to limit process meats and would prefer for you to avoid them! (Therefore, no bologna and no hot dogs!) And he also says to limit nitrates which is found in bacon preservation methods, so stick to organic or use in moderation. The Ketosis phase of Atkins is only 2 weeks at 20 grams or less of carbs per day and then you begin to add in more healthy carbs, in the form of veggies, until you reach the point where you are not gaining/not losing to find your maintenance level. Then back off the carbs just a hair (5-10 grams from maintenance level) until you reach your goal weight. Atkins didn’t give Atkins a bad name. People who do not do their research and assume that if you don’t eat bread or pasta you must be surviving on lunch meats gave Atkins a bad name.

  6. Love this!! I followed at Ketogenic diet for just under 6 months and lost 50 lbs!! Its been over a year since I hit my goal weight and through still limiting my carb intake to a max of 150 net carbs, I have kept off every single pound!! Great article!!

  7. Atkins does not encourage no vegetable eating. Fruits are discouraged because they have so many sugars but you can basically have a veggie fest everyday.

    Note on Ketosis: For me, I can get very sick and vomit similarly to food poisoning and I can’t even keep down water. I have these ketone strips that test the levels of ketones in the urine and every time this happens they always indicate that I have large amounts of ketones. I just need to make sure I’m eating a lot of veggies so that I give my body some carbs. Usually I will lose like 5 or more pounds in like 2 days right before this happens. So if they weight is coming off too fast be careful. So if this happens to you once, its not like your body gets used to it. It will keep happening if you get too deep into ketosis.

  8. Some of these posters and the article’s author might want to read Dr. Atkins’ Diet Revolution. In his original publication he explicitly states that you should stay away from deli meats and hot dogs because they are unhealthy foods. I think too many diet plans are trying to capitalize on the line “Hey, buy our book/program. We’re low carb but not crazy like Dr. Atkins!” Atkins recommends vegetables and meats for only two weeks. Almost immediately you can start adding in dairy, nuts and fruits. There is never a time when vegetables are to be avoided. It’s all in his book.

    • Hi Frank,
      You raise very good points. I was impressed with Dr. Atkin’s work when I first read it. It’s more of an issue of people who don’t read his original books and go out to McDonalds and get 2 burgers without the bun and think it’s good for them. Veggies definitely have a very important place in all of this.

  9. How can you say “excess carbs make you fat” and imply that excess fat and protein don’t? Do calories not exist to you? Why is every Eskimo I see who eats only fat and protein obese while every asian living on white rice is thin? If you exercise and you eat below your caloric needs, it doesn’t matter what foods you eat, you’re going to burn fat. Energy doesn’t come from nothing

  10. This diet is so good for me with depression and candida. My joint pain eases I get more energy, my dark moods lift, my foggy brain goes. Sugar is a poison to a lot of people!

  11. Dr Atkin’s had great work? You mean the guy who is now dead at 73, hardly old. And the guy who had nothing, i mean nothing to show for his work even after 30 years of his ‘research’. Even he admitted this fact.
    Time to do some real research on the people who live the longest disease free and disability free lives. They aren’t on low crab high fat.

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