What You Should Know Before Trying A Ketogenic Diet

What You Should Know Before Trying A Ketogenic Diet

Five people have told me they were going to “try keto” — the most recent after gushing about a mutual friend who has been doing keto, aka the popular ketogenic diet, and getting awesome-looking results. You’ve probably heard rumblings about keto, but what the heck is it? And is it too good to be true?

Let’s first get you caught up on all the hubbub around the ketogenic diet. Keto is an extremely low-carb, moderate-protein, and high-fat diet. You’ll find those on keto gobbling up stuff like fat slabs of bacon, mountains of avocados, and cartons of heavy whipping cream. There’s a lot of enthusiastic fanfare around it, like this comment on Reddit:

What You Should Know Before Trying A Ketogenic Diet

Awesome. And then there’s this one:

What You Should Know Before Trying A Ketogenic Diet

Low-carb diets are nothing new for weight loss. And keto is kind of a low-carb diet with a twist in that you emphasise tons of fat. I spoke to Leigh Peele, NASM certified personal trainer who fields questions on all matters of weight loss, metabolism and nutrition and is author of Starve Mode.

She told me that the original definition of keto is a 4:1 ratio of fats to carbohydrates or protein. That is, for every gram of protein or carb you eat, you would also eat four grams of fat (hence, the avocados and heavy whipping cream). But you don’t have to stick to that exactly as long as your carbs are low and protein moderate enough to properly be “ketogenic.”

Let me explain.

Differences Between Keto and a Low-Carb Diet

Keto’s trump card against the average low-carb diet is that, after consistently depriving yourself of bread, pasta, doughnuts, and any carb source, your body goes into ketosis (between a couple of days and a week).

Ketosis means your body is breaking down fat and releasing large quantities of molecules called ketones into your bloodstream. Your body then uses these ketones as its primary fuel source since you’ve severely limited the body’s preferred energy source: carbs.

Just how few carbs do you need to hit ketosis? Typically less than 50 grams of net carbs per day. That’s barely a regular deli bagel. And that’s assuming you don’t have any other “hidden” carbs from particularly starchy veggies or sugary sauces, for example. However, your personal “ketosis threshold” varies.

You could enter ketosis with as few as 20 grams or as much as 100g. The only way to really tell whether you’re in ketosis is to check via various testing methods (which each has its own problems with accuracy). The easiest to start with are urine test strips.

Does Ketosis Work? 

We’re not really certain about its long-term effects on weight loss specifically. The diet has been used as a medical intervention to help reduce seizures in children with epilepsy that don’t respond well to medication and it’s been shown to have some success.

There’s also some evidence that the diet can help improve blood sugar control for people with type 2 diabetes, but Peele stresses that it is not an automatic fix for blood sugar problems.

We’ve heard plenty of hearsay and stories of short-term benefits on weight loss when people drastically reduce their carbs, but it’s not solely because they went all Texas Chainsaw Massacre on any and all carbs. A review of these studies published in American Journal of Clinical Nutrition found that there was no evidence that carbs (or lack thereof) were the one true thing that stood in the way of you and the bangin’ body of your dreams.

In fact, there’s a lot we don’t understand about the diet’s mechanisms. That includes keto.

From an energy balance standpoint, keto works because, as Yvette d’Entremont, also known as SciBabe, pointed out in response to a commenter here, it’s a diet with a built-in mechanism for calorie restriction.

You’re limiting an entire food group and that automatically eliminates a whole swath of food choices, including doughnuts, cheeseburgers, pizza and Hot Wings Wednesday — all the foods that wouldn’t exactly be figure-friendly if eaten to excess. Plus, eating super fatty foods like a thick cut of finely marbled rib-eye, a whole avocado, and similar things can leave you feeling full for æons.

It also works quickly, unlike the boring un-sexy stuff like eating vegetables and enough protein. Some people can drop 10-20 pounds within a week, which can be encouraging, at least for a time.

But it’s not magic. It’s mainly a change in your eating behaviour and routine and dietary choices, along with the initial loss of tons of water weight (from the lack of carbs).

So You Want to Try Keto…

When it comes down to it, keto is a highly viable diet, as long as you can stick to it. That’s always the big parental advisory sticker on any diet: all diets work if you can consistently adhere to them. If you plan on diving in, there are a few things to note: First, there’s no “oh, I’ll hit pause to inhale this pizza and get back on keto on Monday.”

You’re either in ketosis or you’re not. Otherwise you’re simply forcing yourself to eat an extremely low carbohydrate diet, which is fine if that’s what you want.

Keto is generally safe for the average healthy person, but there are a few caveats. The first is that traditional keto has the potential for protein deficiency because you emphasise so much fat and little protein. “The best one could do is do a more balanced keto diet versus the standard 4:1 ratio to include protein and also take vitamins and minerals to make up for these deficiencies.

Much like how vegans likely need to supplement their diets, those on keto may need to as well,” Peele says.

Peele also warns that if you have an intolerance to high fat foods, had your gallbladder removed, a history of gallstones, fluctuating issues with diabetes, or any medical issue, you should check with your doctor before you try keto.

Going into keto cold turkey is not easy. Some people might experience side effects, one of which is appropriately dubbed the “keto flu” — unpleasant symptoms which include headaches and general weakness during the adaptation phase when your body might be having “carb withdrawals.”

When you’re properly in ketosis, though, keep some mints handy because you may experience a funky change in your breath odor. Oh, and don’t be surprised by changes to your regularly scheduled BM, too.

At the end of the day, keto is not all rainbows and bubble gum. It’s a dietary strategy that requires lifestyle changes and sticking to them to achieve a goal. It is not the Holy Grail of diets, Peele says.

So if you or someone you know has found success with keto, that’s great, but keep in mind that it was your or their circumstances and lifestyle that have helped keto work out better, while it may not work out the same way for others.

This story has been updated since its original publication.


  • Been on Keto for 5 or 6 months now. Coupled with joining a gym and going consistently since January (yeah, I ‘lift’ now, bros), I’ve lost over 10 kilos, centimetres where it counts, and gone from 23% body fat to 16%. It’s a no-brainer really … no way I’m going back to carbs

  • I don’t see this as a diet, more as a way of eating. Same as veganism or vegetarianism or any of ‘diet’ where you actively decide to eliminate a food from your diet. Once you understand why you don’t need carbs and the business of selling carb loaded foods the decision should become much easier to stand by.

  • A very sensible article. I’ve been on again, off again keto for five-years. I lost around 40lbs. total and I now consider me at an ideal weight ( 155lbs. 5′-11″) and feel good. The keto flu is also very real. I remember suffering extreme lethargy, melancholy, headaches, and body soreness, but it lifts after about a week. Is it doable? Yes, but now I tend to cycle in and out of keto every other week. I have taught myself to eat primarily good carbs when I cycle out of keto, eating primarily leafy greens and non-starchy vegetables, along with fruit for dessert.
    One primary benefit of cycling in and out of the ketogenic diet is the focus one places on their food choices. With me, no grains ever, nothing processed, sugar is the demon incarnate, and fast food is a four-letter word.

  • Having done enough Atkins (albeit with veges and some fruit) to drop 10 kg I was happy too.
    Except I gained it back.
    Even that was a loathsome diet, and I cannot imagine what a full-Monty keto would be like.
    Since then I have been doing intermittent fasting, but full fasts on two days a week.
    This I can continue comfortably, and the weight stayed off, not only came off, this time.

  • I went on keto earlier this year because I needed to lose weight to try certain fertility treatments for my PCOS and I was struggling to do it any other way.
    Well, it definitely worked because within a month I had my.period back (after 2+ years of none at all!) and within 6 weeks of that I conceived naturally.
    I can’t handle.keto now I’m pregnant but I think I will definitely go back to it once I focus on losing weight again after birth

  • Understand that the latest research shows that Keto is no better than a high carb diet for fat loss, the only superiority it has is for appetite suppression. More importantly anything remotely close to textbook keto will cause an increase in LDL cholesterol and the jury is in now, increased LDL and Atherosclerotic Cardiovascular Disease is causal.

    • That’s not exactly the whole truth. LDL is demonised, but the so called authorities tend to overlook the “why” and concentrate on the “what”. It is required by your body to transport necessary proteins and prevent damage from toxins. Keep in mind your body produces 13000mg of cholesterol per day on its own so cholesterol isn’t bad. Just because LDL is present at the site it is trying to heal doesn’t make it the culprit for heart attack. It’s like saying paramedics are the cause of death by heart attack. There is an association but that statement is totally not true! See https://youtu.be/dWMaXJtoXBo

    • Yep. It’s not a lifestyle! For short bursts, it’s life changing in the best of ways.

    • That article you shared was written by someone who was trying to flog their own book (the end of the article recommends a book written by the article author).

      The evidence is in the results of those who have done it properly. I’ve had amazing success in losing weight on keto (10+ kilos so far, unfortunately I’ve gone off the wagon a couple of times which has hindered results), but I have also had success on other diets. As this article points out, keto has built-in assistance mechanisms in that its better for satiety/curbing hunger cravings and forces one to be more mindful of what they’re eating.

  • Great article. Couple of key things for those starting. You can avoid keto flu and cramps by supplementing extra salt in your diet (roughly 1 teaspoon a day) as you don’t retain as much water and hence less minerals. This water loss also is why people see a significant weight reduction on the first day or so. You also need to maintain adequate magnesium/potassium intake for the same reason. Vegetables are extremely important for this and to keep your liver healthy while taking in high fats. You can get away with less protein as your body releases a chemical whilst in ketosis which results in your body requiring less protein then the equivalent person in an average diet. But, if you’re hitting the gym there is no issue with increasing protein intake by about 5% or so. It won’t harm ketolyf

  • Hey, I’ve done a few stretches of Michael Moseley -style low cal keto since Jan 2017. It works. I’ve gone from 138kg down to 101 and I am into the last major stretch right now. I expect to shed 14 kg in 8 weeks and to then put about 4kg back on… it’s water.

    Whatever you decide, I urge you to get the Blood Sugar Diet book he wrote from Kmart etc. It’s like $16. The first third is a primer on stuff we all half know, plus a round up of research.
    The foreword is written by a Professor from Newcastle Uni in the UK.

    I’m in my 40s, I’ve seen a few fads come and go. Some people are treating Keto like a fad and will hurt themselves and others who believe them without being sensible. Keto is not a long term lifestyle. It’s a tool and I suspect one best used for short bursts of very low cal effort. Mine is 800 calories. Yep. And it is so much better and easier and more beneficial than I expected. You go into a partial starvation mode with no carbs so the body starts breaking down fat throughout the body, including the liver and pancreas. There is evidence that any fat in those organs has a lot to do with disease. Fat breaks down into ketones including acetone, that you pee out, turning ur pee yellow and letting you know that it’s happening. You then split ketones for energy use in the body… ketosis. A byproduct is a natural chemical similar to the party drug GHB. You actually feel less hungry and sharper – clearly an evolutionary mechanism to help us survive dangerous situations.

    For me, the results have been excellent. The control and seeing change are outstanding. You are doing something hard that has a great outcome. That is powerful. And I am off the diabetes pills. But the big thing is taking a holiday from a lifetime of eating habits and your relationship with food. It makes you think. Moseley is all about what you do next … The diet isn’t a mountain you climb and then you’re done: it’s a period of pausing your relationship with food so you can get ready for what comes next.

    I’ve made up my own lazy way to do the diet with lots of frozen vegies and bags of coleslaw mix, plus endless tuna and flavours. I have one main meal now plus coffees and tea and water through the day. That would have seemed crazy to me not long ago but it works. I only eat breakfast sometimes on weekends or when out hiking. Which I do a lot of now!

    I’m far from done but I enjoy food much more now. There is no guilt plus I see each thing for what it really is. Some childish magic has evaporated, but I can eat anything and enjoy it in ways I don’t think I have for decades. But Keto is not a lifestyle. It will hurt you in the long run. No way. Read that Moseley book. I’ve got a few copies. Message me and I’ll send you one :-).

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