A Closer Look At The Ketogenic Diet: The Pros And Cons Of A High Fat, Low Carb Way Of Eating

Could a carb-limiting regimen help you kick your body’s functionality into high gear?

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If thinking about the ketogenic diet brings to mind the low carb diet craze of the late ’90s and early aughts, you’re not alone. The popularity of the ketogenic diet and its many offshoots has ebbed and flowed over the 50 years since its introduction. While some health professionals warn against the use of a ketogenic diet to support weight loss, others firmly believe that this eating plan is a stand-alone solution to chronic health issues associated with obesity and high sugar levels. But did you know that the ketogenic diet has its roots in a field of medicine entirely unrelated to weight loss—or that it’s still being used for its original purpose to this day?

Where did the ketogenic diet come from?

The ketogenic diet’s origin story surprisingly begins thousands of years ago in ancient India and Greece, where it had nothing to do with weight loss. Physicians began observing that fasting diets had a positive effect on patients suffering from epilepsy for reasons that were unclear at the time. Fast-forward to America in the 1920s, when several doctors noticed a reduction in epileptic seizures when their young patients were put on a low carbohydrate diet that entailed the strict exclusion of starches and sugars. In 1921, endocrinologist Rollin Turner Woodyatt discovered ketone bodies, a series of three water-soluble compounds that were made by the liver of patients who ate high fat diets but extremely restricted carbohydrates. In 1924, he introduced the ketogenic diet as we know it today.

The Ketogenic Diet’s Role in Epilepsy Management

The ketogenic diet is still used as a means to treat epilepsy in children who have a resistance to anti-seizure medications or other epilepsy treatments. Annie Tsang, a registered dietician based in Vancouver, British Columbia, explains that in addition to epilepsy treatment, the ketogenic diet is also being studied for its effect on other chronic health issues, which she says could potentially affect the treatment and management of Parkinson’s and Alzheimer’s diseases, type 2 diabetes, autism, cardiovascular disease, and multiple sclerosis.

The Ketogenic Diet as a Weight Loss Method

The ketogenic diet clearly has a lot to offer in terms of epilepsy treatment, but how exactly does it come into play for those looking to lose weight or prevent long-term health issues related to obesity?

The Science Behind Ketosis

To understand the ketogenic diet, we have to unpack some basic scientific truths. A good starting place? Understanding that when we consume carbohydrates (and we love carbohydrates—the mean daily carbohydrate intake for Americans sits at just under 50 percent of overall caloric consumption), our livers automatically convert them into glucose. Glucose moves throughout the body via the blood stream, where it becomes blood glucose that can be used for fuel. A ketogenic diet entails an intentional divergence from the typical body’s reliance on glucose for energy. The term “ketogenic” refers specifically to the ketones your liver produces when it’s starved of sugar and carbohydrates. But what exactly are ketones? When your body has low levels of glucose, it turns to burning fat for energy instead of relying on blood sugar. This process results in the generation of ketones, an organic compound produced by the liver when fats are broken down to serve as a non-glucose form of fuel for the body. Specifically, ketones are produced and used as fuel when you fast or eat a diet very low in carbohydrates and high in fat. When following a ketogenic diet, the goal is to use the ketones generated as fat breaks down as your primary source of energy instead of glucose—thus the keto diet’s fat-burning claim to fame. Still, it’s important to note that merely eating a ketogenic diet isn’t a guarantor that you will lose weight, and keeping calorie consumption within a healthy range is still imperative as with any other dietary regimen.

What about protein?

The ketogenic diet has become synonymous with low carbohydrate and high fat intake, but where does protein come into play? Including adequate amounts of protein in your diet is imperative to good health since the human body is incapable of making nine out of the eighteen essential amino acids it requires on its own. When the ketogenic diet is marketed as a weight loss tool, emphasis is often placed on consuming high levels of protein and fat, which is an inaccurate interpretation of a true ketogenic diet.

The Keto Flu Blues

When too much protein is consumed on a ketogenic diet the body begins to convert protein into glucose in a process called gluconeogenesis. As with carbohydrates, gluconeogenesis can lead to spikes in blood sugar levels and a reduction of ketones that can be used as a source of energy for your body. When you first begin the ketogenic diet, you may experience unpleasant symptoms that have come to be associated with a phenomenon known as the keto flu.

Symptoms of Keto Flu

The keto flu is the name for a group of symptoms that can occur when you’re just starting out with the ketogenic diet or when you’re moving back and forth between consuming smaller and larger amounts of protein. The keto flu most often occurs in people who are just beginning their switch to a low carbohydrate diet, although for some individuals the effects can last up to five weeks. Common symptoms can include tiredness, headaches, irritability, stomach upset, sugar cravings, difficulty sleeping, and even bad breath.

How to Work Through the Keto Flu

Amy Berger, MS, certified nutrition specialist, nutritional therapy practitioner, and author of The Alzheimer’s Antidote stresses how normal symptoms of the keto flu actually are. She says:

When people are brand new to this way of eating, if they’re transitioning to it from a high carb diet, they might experience what we call the keto flu, or the low carb flu—headaches, dizziness, nausea, light-headedness, etc. This is normal and to be expected. The worst of it should pass in a couple of days, and people can help ease this transition by being sure to get plenty of salt/sodium, and maybe extra magnesium and potassium (especially if they have leg cramps). The dramatic decrease in carbohydrates is a bit of a shock to the body, and the rapid change in blood glucose and insulin levels changes the way the kidneys hold on to electrolytes. People on a very low carb diet, especially at the beginning, really need to be sure to get enough salt.

A Closer Look At The Ketogenic Diet: The Pros And Cons Of A High Fat, Low Carb Way Of Eating
Berger also adds that there may be a decrease in stamina for individuals who are athletes or who work out regularly. “For athletes or people who work out a lot, they should expect to have a decrease in athletic performance (power, stamina, strength), but this is temporary. As the body adjusts over the course of weeks and months, their usual level of performance will come back, and it often then surpasses where it was. But they should be prepared to have a slight decline at first.” During this time of transition, it’s especially important to listen to your body and give yourself plenty of rest as you get used to a new way of eating.

The Ketogenic Diet and Weight Loss

Due to the popularity of dieting methods in general, it would be easy to brush off the ketogenic diet as merely another fad diet with few actual success stories. The ketogenic diet has, however, proven itself incredibly effective when it comes to weight loss. An study published in Nutrition & Metabolism in 2004 notes that adherence to the ketogenic had a noticeable effect on immediate weight loss in male and female participants, with male participants achieving a marginally greater weight loss than female participants. Another study indicated that weight loss is achieved at a faster speed when subjects adhere to a ketogenic diet as opposed to those who ate low calorie, low fat, and high carbohydrate diets.

How to Adhere to a Ketogenic Diet and When to Expect Results

It’s crucial when undertaking a ketogenic diet that you follow strict nutritional guidelines. Namely, it’s important to restrict your carbohydrate intake to 20 grams or fewer each day and to consume plenty of water. It takes between two and seven days for your body to enter a state of ketosis in which it’s using ketones instead of glucose for energy. Ultimately, the weight loss caused by this transition will be dependent on your gender, age, current weight, and level of exercise.

What can you eat on the ketogenic diet?

By now you know that the ketogenic diet limits carbs, includes plenty of fat, and involves moderate protein intake. So what does that mean in terms of the foods you’re allowed to eat?

Get ready to enjoy the following:

  • Healthy fats and oils such as olive oil, nut oils, avocado oil, coconut oil, other cold pressed oils, avocados, butter, and ghee
  • Nuts such as macadamia nuts, Brazil nuts, and pecans
  • Fatty fish such as salmon, trout, tuna, snapper, and halibut (check to make sure these are Ocean Wise–friendly options)
  • Meat such as beef, veal, poultry (aim to eat dark meat as it contains a larger proportion of fat to protein), pork, organ meats, lamb, and goat
  • Non-starchy vegetables such as leafy greens, Brussels sprouts, broccoli, onions, asparagus, bell peppers, cucumbers, zucchini, cauliflower, and celery
  • Fruits such as cranberries, strawberries, blackberries, cherries, raspberries, and blueberries

Beginning a new diet can be daunting as it’s easy to think of a long list of what you can’t eat instead of what you can. Berger offers this advice to anyone thinking about transitioning to the ketogenic diet:

If someone is feeling down or scared about going without what are probably some of their favorite foods, I would say to focus on all the things they can have, rather than on the things they’re eliminating. Think about delicious steaks, pork chops, cheese, bacon and eggs, lots of beautiful and delicious roasted vegetables, nuts, berries…there are so many amazing foods that are perfect for this way of eating that it helps to think about that, rather than pining for the things you should stay away from.

Foods to Avoid While Adhering to a Ketogenic Diet

While carbohydrates are clearly the enemy of the ketogenic diet, there are many foods that contain loads of carbohydrates even though it might not be obvious.

Watch out for and avoid the following:

  • Grains and grain products of any type (including bread, pasta, and rice)
  • Legumes
  • Artificial sweeteners
  • Overly processed foods
  • Low- and zero-carb convenience foods
  • Dairy products
  • Alcohol
  • Tropical fruits (which tend to be high in sugar)
  • Fruit juices and soda
  • Potatoes

If this sounds like a challenge, remember there are literally hundreds of websites and cookbooks that are completely dedicated to providing amazing recipes that are low in carbohydrate but loaded with flavor!

How to Know if a Ketogenic Diet is Right for Your Needs

As with any change in dietary habits, it’s important to consult with a professional before making any drastic decisions. While the ketogenic diet has been proven effective when it comes to short-term weight loss, Tsang recommends considering a more well-rounded approach to dieting:

As all macronutrients are important for our health, we generally recommend a more balanced diet to help with weight loss. While a high protein diet might be a preferred recommendation, every individual’s need is different—there is no “one size fits all” when it comes to our body, our diet, and our metabolism. This is why it is always important to seek a registered dietitian to discuss your personal nutritional goals.

It’s tempting to consider the ketogenic diet if you’re looking to lose pounds in a hurry, but it’s also wise to consider the long-term sustainability of a diet that restricts an entire macronutrient group so drastically. As Tsang says, “There could be other methods that help lose weight a little quicker but I always suggest slow, steady weight loss as this will give you a higher chance of maintaining the weight.” Looking for some ketogenic breakfast inspiration? This Southwestern egg yolk scramble comes together in under 10 minutes and makes a great breakfast or late-night dinner when you don’t feel like cooking an multi-dish meal.

Southwestern Egg Yolk Scramble

Serves: 1

Nutrients: 13.5 grams of carbohydrates, 11.5 grams of protein, 39.8 grams of fat, 440 calories


  • 1 Tbsp. butter, salted
  • 3 egg yolks
  • 1 Tbsp. water
  • Pinch of chili powder
  • 1 cup of baby spinach, torn or cut into small pieces
  • 1 oz fresh salsa
  • ½ avocado, diced

Special Equipment:

  • Skillet
  • Spatula


  1. Melt the butter in a skillet over medium heat.
  2. In a small bowl, whisk together the egg yolks, water, and chili powder. The water will help create fluffy scrambled eggs by steaming the yolks as they cook.
  3. Scramble the eggs by carefully pushing the yolks into the center of the skillet as they cook. Stir in the baby spinach during the last 30 seconds of cooking.
  4. Top the scrambled egg yolks with the fresh salsa and diced avocado. Enjoy!
Ashley Linkletterhttps://ashleylinkletter.com/
Ashley Linkletter is a food writer and photographer based in Vancouver, British Columbia. Her work has appeared in Culture Cheese Magazine, SAD Magazine, EAT Magazine, and she is a regular contributor to Weight Watchers Canada. Ashley’s area of expertise is cheese and wine, and she’s authored a biweekly cheese column for Scout Magazine called Beyond Cheddar as well as writing about Canadian cheeses for Food Bloggers of Canada. Ashley’s personal blog musicwithdinner explores the emotional connection between food and music while providing original recipes and photographs. She strongly believes in cooking and eating as powerful mindfulness exercises and encourages her readers to find pleasure and a sense of calm while preparing food.