Before we get started on ketogenic diets, we need to understand a bit about our body’s metabolism. Because the ketogenic diet is a diet that deliberately alters how our metabolism works.
When we eat food our stomach and intestines (our digestive tract, if you will) breaks down our sandwich (or whatever we just ate) into its tiny parts (carbohydrates/sugars, protein, fats, vitamins and minerals).
Carbohydrates are broken down into individual sugars. Fats are pulled out of the food and packaged for transport into the blood (because oil and water don’t mix, right?) All the vitamins, minerals and energy that our body needs are transported into the blood and sent straight to the liver. The liver packages everything up into ways our body can use. Everything else stays in the intestine and gets excreted as number two’s.
Meanwhile, sugar leaves the liver and is pumped through the blood for our muscles and cells to pick up and use for energy.
Any extra energy that is not needed is stored. Sugar is stored in the liver, this is called glycogen. Fats and cholesterol are pumped around the body for various reasons, to provide cells with energy being one of them. Any extra fats are stored in our adipose tissue, for energy for later. Now imagine you’ve just had a big dinner. Your body is doing the above and is in the fed state.
Then you go to bed and you sleep for say, 10 hours. After a few hours your body runs out of sugar and fats from your meal, for energy. Your liver starts turning the glycogen back into sugar. Sugar gets pumped back into your blood, to make sure your body has enough energy. Your body also starts breaking down more fats and releasing fat for energy. This is what happens in a fasted state.
Now imagine you wake up with a full-on flu. You can’t eat, you feel too sick. But your body still needs energy to carry on its basic functions. So, in the absence of incoming food, your body continues to use up its energy reserves, until eventually your liver runs out of glycogen and sugar. This usually happens within 24 to 48 hours. Luckily, we have lots of fat storage on our bodies, so we won’t starve yet! But we now need more fat for energy so the process that involves breaking down fat for energy gets sped up.
BUT! Your brain has an absolute requirement for glucose. Your muscles can easily convert fat into energy, but your brain can’t. So your body switches into a metabolic phase called ketogenesis. This is when your body breaks down fat and turns it into ketones. Ketones are wee alcohols that are able to act like sugars and feed your brain when you are in, what’s basically, a starvation phase. This phase is called Nutritional ketosis. It’s a natural metabolic phase that saves our butts during periods of starvation.
NOTE: Nutritional ketosis is very different from diabetic keto acidosis. The difference is the amount of ketones in the blood. In nutritional ketosis it’s low and in keto acidosis the ketones are so high that they make the blood acidic and can cause death.
So, what is the Ketogenic diet?
The ketogenic diet is designed to put your body into starvation mode, or nutritional ketosis.
Basically, instead of starving your body you are choosing not to put carbohydrates in your body. Carbohydrates are the macronutrients in our food that break down into sugars.
Think: potatoes, pasta, bread, cereals, sugar, fruit, rice, oats, kumara, carrots, lollies, most chocolates, tomatoes etc etc etc.
I think you get the idea, that a lot of foods contain carbohydrates. Some are packed with nutrition like fruits, vegetables and unrefined carbohydrates. Some are less nutritious, but delicious, like chocolate and according to my kids, lollies.
The ketogenic diet aims to have between 5 -10% of our total energy intake from carbohydrates. This is enough to keep our body in nutritional ketosis.
Another way to look at that is 20 to 50 grams of carbohydrates each day. 20 grams of carbohydrate is the same as: 1 large potato, or 1 piece of bread, or 1 small apple, or 2 small peaches, or 1 banana, or 2 – 3 biscuits. It’s not a lot, right?!
On the ketogenic diet you would focus your foods on leafy green vegetables and other low carb veggies such as mushrooms, courgette, celery, cucumber, spinach, broccoli, avocado, cauliflower, asparagus, bok choy. You’d fill up on meat, chicken, fish, nuts, seeds, eggs. You’d use nut-based fats, olive, coconut oil and butter and extra dark chocolate. The main source of energy would be from fats generally around 75%, 15% from protein and 5% from carbs.
You wouldn’t eat fruit (apart from some berries), any grains, breads, cereals, pizza, biscuits, cake, most dairy products, starchy vegetables like potatoes, pumpkin, parsnip, kumara, corn, crackers, lentils, beans, etc.
Basically the list of what you wouldn’t eat is longer than the list of food you would eat.
The ketogenic diet was originally designed as a medical treatment for children with refractory epilepsy. I do know of some people with type 1 or type 2 diabetes , who manage their diabetes with a ketogenic diet. I also have a few patients with brain cancer and their specialist has recommended a ketogenic diet. But, there is no evidence that proves a ketogenic diet is beneficial for diabetes or brain cancer, above other ways of eating, and we don’t know what the long term health effects of the ketogenic diet is. However, there is good evidence that a moderately low carb way of eating in diabetes is helpful. And some animal studies have been done on the ketogenic diet, with mice who have brain cancer, with some excellent results. More studies are being done, so watch this space!
What we do know, is that the diet that works the best, is the diet the individual can stick to.
Nowadays the ketogenic diet is fashionable as a weight loss diet.
The problem with the ketogenic diet is:
- Constipation! Due to the carbohydrate restriction (not being able to eat fruit or many vegetables) it is very difficult to be able to eat enough fibre. Fibre is essential for our bowel health and keeping us regular.
- It’s expensive! You are relying your main sources of energy from expensive foods, such as meat, fish, nuts, seeds, oils. the average New Zealander doing this diet properly, will be spending $300+ per person, per week. I know families who have $50.00 a week for a family of 4, so this alone is a major barrier.
- You can’t cheat on it. If you have a day where you want to eat an orange you’re going to blow your nutritional ketosis out of the water in one juicy mouthful
- It’s restrictive! Food is not just about nutrition, it’s about sharing meals with family and friends, and enjoying cultural and traditional foods. You can’t do any of this on a keto diet, because so many foods are major no-no’s. And what if you actually want to eat a piece of cake on your birthday? What if there is a shared morning tea and none of the foods fit your diet? Your mental health and the social aspects of food and eating are so important and equally as important as our physical health.
ShouId you go keto?
If you have a medical condition that you think may benefit from going keto (epilepsy, diabetes, brain cancer) speak with your specialist about it first. You may need help adjusting medications, or there may be other factors that you need to discuss with your doctor first. Make sure you see a registered dietitian to help you manage it, as it’s a specialist diet and you may need the support to get you started and to make sure you are doing it in a healthy way. It may be that keto isn’t going to work for you, but a moderately low carb approach will. Make sure you get advice from a health professional you trust.
If you are otherwise healthy and are thinking “but I want to lose weight”. There is some evidence that keto will help you lose weight, in the first few months, but there is very little difference between diet types in the long term. And remember the best diet is one that you can stick to. Healthy eating is healthy eating for life and this does mean it’s ok to have and enjoy all foods. To maintain optimum health: think mostly plants, unprocessed foods as much as possible. Eat to appetite and enjoy all foods.
Weight loss doesn’t necessarily = health. And our health behaviours (eating 5 + a day, not smoking, exercising regularly and not drinking too much alcohol) are more predictive of our health than whatever diet we choose to do or whatever number is on the scale.
If you want help with how you are eating, think a keto diet might be right for you or need help with managing your diabetes, get in touch! I am a Nutritionist and Registered Dietitian. I offer nutrition consults from my Auckland based clinic and and on Skype.