The Science of the Ketogenic Diet and What to Expect if You Decide to Try It

Today’s health and nutrition landscape has given rise to a seemingly endless list of diets to choose from: weight loss, detox, intermittent fasting, paleo, low- fat, high- fat, low- carb and many more. It seems like every time we turn on the TV or look at a magazine, there’s another new diet promising “real results.” From pills, to berries, to shakes and meal plans, we are sold ideas about weight loss that are quite confusing and overwhelming.


Newer research has confirmed what practitioners of holistic medicine have long known, that limiting carbohydrate intake and eating healthy fats in combination with good portions of fruits and vegetables can lead to significant weight loss within a healthy period of time. Unsurprisingly, many find it difficult to heed this advice since it sits in stark contrast to the messaging we’ve received for decades: that fat is bad and should be avoided at all cost.

We have started to see this philosophy break down in the face of research showing us just how important fats are for our overall health. Not only but the restriction of fat intake can actually lead to poorer health outcomes. We have learned that the claim that saturated fat increases the risk for heart disease came out of bad science and is unfounded. While saturated fat raises overall cholesterol, this is not necessarily a bad thing as it raises both HDL (good) and LDL (bad) cholesterol. No direct link has been found between dietary saturated fat intake and heart disease. In addition, a key problem with the research is that it does not differentiate between eating organic and 100% grass fed animal products with saturated fat from eating conventional animal products contaminated with chemicals and raised eating corn, which is not what most animals are genetically evolved to eat. An egg from a conventional hen compared to a truly pasture raised hen that eats grass and bugs has a very different composition of fats and a different impact on our bodies and inflammation levels.

The low carb high fat (LCHF) diet has emerged as more and more people turn away from simple carbs and embrace fat.


The science behind the concept of eating more fat and less carbohydrates is quite sound. You see, fat is very satiating, so you become fuller more quickly than you do with carbohydrates. Thus, while fat has more calories per gram than carbohydrates, you will end up eating less of it. Have you ever noticed yourself mindlessly finishing an entire bag of chips before you realize what happened? That’s because you can eat a lot of carbohydrates before ever feeling ‘full’! It’s not quite as easy as you may imagine to eat an entire jar of nut butter!

Carbohydrates get broken down into glucose before being released into the bloodstream. If the carbs are “simple”- things like white bread, candy, and fruits- they get broken down very quickly and cause a spike in blood sugar levels. More complex carbs like brown rice and whole wheat pasta take longer to break down and result in a more gradual rise in blood sugar. In both cases, the pancreas will release insulin in response to rising blood sugar. Insulin binds to cells in the body which enables glucose to enter. As you might infer, when we eat a large amount of simple carbs, we experience a spike in blood glucose levels followed by a “sugar crash” once insulin gets released by the pancreas, cells take in glucose, and blood glucose levels drop back off. You may suddenly feel hungry again because simple carbs like sugar and white bread get broken down by our bodies very quickly and because insulin stimulates our appetite.

When we consume large amounts of sugar over longer periods of time, the cells in our body become less sensitive to insulin and we run the risk of developing type II diabetes. It’s as if the cells get tired of the insulin constantly knocking at the door and they become less responsive to it. Insulin resistance causes the release of even more insulin into the bloodstream to try and control the blood glucose levels, which puts a strain on the pancreas. When our body can no longer keep blood glucose levels within normal range, Type II Diabetes has set in. Avoiding refined carbohydrates will help keep our bodies out of this cycle and keep Type II Diabetes at bay.

So that is the carbohydrate piece of the LCHF diet. The fat piece – consuming foods with high fat content – will cause the body to switch from burning carbs to burning both the fat you consume and your stored fat as a primary fuel source.


When starting the LCHF diet, it is common to go through a withdrawal phase. Sugar causes the release of dopamine because our brain perceives it as a good thing and triggers the reward pathway. Sugar goes in, feel-good brain chemicals gets released, more sugar is craved, more chemicals get released. This causes sugar cravings to increase over time and eventually we become addicted. When we cut carbs out, we unsurprisingly go through withdrawal. In fact, sugar has been shown to induce the same or worse withdrawal symptoms as cocaine, and has been shown to be eight times more addictive than cocaine. So, while some people think that it’s the lack of eating that’s making them feel lightheaded and nauseous, it’s most likely the sugar withdrawal that is the culprit.

In the adaptation phase, without an adequate supply of glucose in the bloodstream, the body switches over to burning fat as its primary fuel source. During this period, it is common to experience symptoms, such as: brain fog, fatigue, headaches, lightheadedness, insomnia, bad breath, low-level dehydration, and a feeling of heaviness throughout your body. The good news is, the adaptation phase is short-lived and will likely pass after the first week.


There is a whole range of benefits to the high fat, low carb diet, some of which include:

  • Decreased risk of fat storage, high blood pressure, heart attack and cardiovascular disease

  • Potential for fat loss and muscle gain

  • Decreased inflammation

  • Decreased cravings and appetite, preventing potential of overeating

  • Improved blood markers such as HDL/LDL, triglyceride, and glucose

  • Decrease in stress on digestive system


An potential meal plan following the high fat, low carb method would include approximately 50% percent of your calories from healthy fats, 25% from carbs, and 25% from protein. Don’t confuse healthy fats with trans fats and “fatty foods” however. You want to get your fats from foods such as nuts, avocados, butter, olive oil, coconut oil, and smaller quantities of animal products such as grass fed meat, pastured poultry (chicken, turkey, duck), wild oily fish (salmon, mackerel, sardines), whole pastured eggs, and pastured fatty cheeses.

Maximize intake of cruciferous vegetables like broccoli, cabbage, leafy greens, asparagus and cucumber and moderate intake of vegetables high in carbohydrates, like potatoes, sweet potatoes, corn, beets, and peas. Remember to avoid low-fat, processed, sugary, refined products, as well as carbohydrates such as wheat, oatmeal and rice. Avoid fast foods, soda and alcohol. Focus instead on eating the freshest, closest-to-nature whole foods you can access. A good rule of thumb to follow is if it has a long expiration date, it is best to avoid if possible.