The Nitty Gritty Of Keto
Take a deeper look at the science behind the Keto diet.
What is Keto?
Keto is a sustainable and enjoyable high-fat, moderate-protein, low-carb (70% fat, 25% protein, 5% carbohydrate) eating lifestyle. It involves drastically reducing carbohydrate intake and replacing it with fat. This reduction in carbs puts your body into a metabolic state called ketosis. In ketosis, your body becomes incredibly efficient at burning fat for energy. Ketosis also turns fat into ketones in the liver, which can supply energy for the brain (1). Keto can also cause significant reductions in blood sugar and insulin levels. This, along with the increased ketones, has some health benefits.
What are ketones?
Ketones, or ketone bodies, include three simple molecules: β-hydroxybutyrate (βHB), acetoacetate, and acetone. βHB is the main human ketone found in the blood. Ketones are often referred to as the “4th macronutrient” because, like carbohydrates, fats, and proteins, they can be broken down by the body as fuel. However, they are not found in natural foods; they are made by our livers from dietary fat or body fat.
Why do we need ketones?
Our brains have big appetites. Your brain weighs 2-3 pounds but consumes 500 kCal, or about 20-25% of your daily caloric intake, per day. The brain uses glucose as fuel, but during our evolution glucose usually wasn’t available in our diets. Rather than eat up all of our lean body tissue by turning muscle protein into glucose (gluconeogenesis), our bodies evolved the ability to make an alternative brain fuel from our body fat: ketones! Without ketones, we wouldn’t have survived evolution. Ketones can also fuel most other organs, like our skeletal muscles and hearts.
How does the ketogenic diet cause weight loss?
There is no better tool to lose weight, and sustain weight loss, than the ketogenic diet. This is mostly because restricting carbohydrates:
- Forces your body to learn to use your fat as fuel
- Decreases levels of the hormone insulin, which is your fat-storage hormone (2)
In addition to teaching your body to learn to use your fat as fuel and decreasing insulin, new complementary data out of Harvard shows the low carb diets such as Keto also change your metabolism to increase energy expenditure (3). In other words, you increase the speed of your metabolism, thus burning more calories.
Is the Keto diet hard?
The short answer is no. While it does take time to learn what works best for your body, once you have it down, Keto can be one of the most enjoyable and sustainable lifestyles in the world.
What is Ketosis?
Ketosis is a metabolic state in which your body uses fat for fuel instead of carbs. It occurs when you significantly reduce your consumption of carbohydrates, limiting your body’s supply of glucose (sugar) which is the main source of energy for the cells.
Following a ketogenic diet is the most effective way to enter ketosis. Generally, this involves limiting carb consumption to 20 to 50 grams per day and filling up on fats, such as meat, fish, eggs, nuts, and healthy oils. It’s also important to moderate your protein consumption. This is because protein can be converted into glucose if consumed in high amounts, which may slow your transition into ketosis (4).
Blood, urine, and breath tests are available to help determine whether you’ve entered ketosis by measuring the amount of ketones produced by your body. Certain symptoms may also indicate that you’ve entered ketosis, including increased thirst, dry mouth, frequent urination, and decreased hunger or appetite (5).
What is the Keto Flu?
The Keto flu is a set of symptoms that may appear two to seven days after starting a ketogenic diet and generally last 24 - 48 hours (6). Symptoms include the following:
- Headache - Caused by low blood sugar and carbohydrate withdrawal
- Foggy brain - Caused by low blood sugar and carbohydrate withdrawal
- Fatigue - Caused by the body building new enzymes and losing its main source of energy at the same time; additionally, a high level of circulating fats displaces tryptophan from its carrier, inhibiting tryptophan from acting as a precursor to serotonin production. Low serotonin leads to fatigue.
- Irritability - Caused by low glucose, serotonin, potassium, sodium, and B Vitamins in the brain.
- Nausea - Caused by the high fat consumption, which takes longer to digest and absorb.
- Difficulty sleeping - Caused by lack of serotonin, which is needed to produce melatonin; insomnia is also a symptom of sugar withdrawal.
- Constipation - Caused by no longer eating fiber rich carbohydrates.
- Dehydration and frequent urination - Caused by the body’s liver and muscle glycogen, which causes a lot of water loss because every gram of glycogen is suspended in 3 grams of water; lower insulin causes the kidneys to retain less water; low sodium increases the release of norepinephrine which is a stimulating adrenaline hormone.
How to Overcome the Keto Flu
If you’re experiencing the Keto flu, make sure you are doing the following to decrease its duration or lessen your symptoms.
- Eat enough fat
- Take over-the-counter headache, pain killer, or anti-inflammatory medication
- Increase sodium intake
- Drink bone broth
- Drink water
Benefits of Keto
1. Weight Loss
Weight loss is probably the most commonly cited health benefit of the ketogenic diet, and it’s not one to overlook. With keto, weight loss is real and effective for one simple reason: it helps people convert from a carb-heavy, carb-burning diet to a fat-heavy, fat-burning diet. A diet high in carbs induces bloating, weight gain, and poor health and relies on carbs for energy. A high-fat, moderate-protein, and very low carb diet curbs your appetite, allows you to eat until you’re satiated, and burns fat from your body and your foods for energy. Keto can also reduce your risk factors for obesity-related diseases and disorders, including diabetes, heart disease, stroke, and certain cancers.On a keto diet, you get to eat your fill of satiating foods loaded with good fats, which triggers a fat-burning metabolic process known as ketosis. Once your body is acclimated, this leads to increased energy and ability for physical activity.
2. Reduced Appetite
Imagine not feeling those food crashes and carb cravings. That’s the keto life. You eat, then you’re satisfied…for a long time! Once your body has settled into the diet, it works more efficiently, burning the fats in your food and your body and never embarking on the wild ride that is the highs and lows of a carb/sugar laden diet. Without the sugar peaks and crashes, cravings disappear, and you feel satisfied.
Each day on a keto diet, you consume and track macronutrients (“macros”), or the total amount of calories from fat, protein, and carbs you should eat per day based on your height, weight, activity level, age, and goals. But not all macros are the same (7). Each has a specific amount of energy or calories:
- Carbohydrates have 4 calories per gram
- Protein has 4 calories per gram
- Fat has 9 calories per gram
Fats are more satiating because they provide you with the same energy per gram as both protein and carbohydrates combined.
That’s not the only reason your appetite is reduced on a keto diet. Once you get into ketosis, you generally don’t experience the blood sugar level peaks and valleys – and the consequent hunger pangs – that you do on a carbohydrate-heavy diet. Hormones, in this case insulin, cholecystokinin, ghrelin, and leptin, play a strong role in the lack of hunger because they influence the feeling of being satiated (8).
Ketosis has been shown to suppress ghrelin (a strong appetite stimulator). In fact, in a study where participants were put on a ketogenic diet for eight weeks and then reintroduced to a standard diet, participants in ketosis experienced a reduction of circulating concentrations of several hormones and nutrients that influence appetite (9).
Inflammation is the body’s natural immune response to help heal and fight infection. But persistent inflammation in too-high quantities can cause unpleasant symptoms, such as pain, joint stiffness, swelling, fatigue, and more acute physiological results.
When you’re on a keto diet and regularly in a state of ketosis, your body produces ketones, specifically BHB (ß-hydroxybutyrate), which is a strong anti-inflammatory chemical. BHB helps to inhibit the inflammatory pathways (NF-kB and COX-2) and also activates the AMPK (AMP-activated protein kinase) pathway, which assists in inhibiting the inflammatory NF-kB pathways. Additionally, BHB has been shown to exhibit effects similar to pain-relief drugs, such as NSAIDs, by inhibiting the COX-2 enzyme.
Another anti-inflammatory influence is the ketogenic diet itself; the keto diet helps promote the consumption of anti-inflammatory foods, such as eggs, olive oil, coconut oil, avocados, and other foods high in omega-3s, all of which are heralded for their anti-inflammatory effects (10). The diet plan also promotes the avoidance of inflammatory foods. The lists below feature some popular anti-inflammatory and inflammatory foods.
- Olive Oil
- Coconut oil
- Fatty fish
- Bone broth
- Processed foods
- Refined sugar
- Starchy vegetables
- Processed oils (canola, corn, safflower)
When people think of high-fat diets, they almost instantly think of high cholesterol levels. Yet more and more research shows that fat is not to be feared, but has been the scapegoat for the real culprits of cardiovascular and obesity issues among Americans today: processed carbohydrates and diets high in sugar.
On a ketogenic eating plan, many people experience a decrease in total cholesterol, a decrease in triglycerides, and an increase in HDL (11). Although some people may see a rise in cholesterol on a ketogenic diet, those people would likely see an increase regardless because rapid weight loss, be it water weight or body fat, can lead to a temporary, short-term rise in LDL cholesterol. Consequently, it’s often recommended to wait six months after starting a ketogenic diet to test your lipid panels, or to wait until your weight loss has tapered off.
5. Diabetes & Blood Sugar Control
Since you eliminate sugar and most carbohydrates on a keto diet, it’s not hard to understand why it’s great for blood-sugar control. The less sugar and carbs you eat, the less sugar in your bloodstream. This is why, after starting a keto diet, most people will notice a decrease in their blood sugar almost immediately. In fact, the effects are so immediate, it’s recommended that diabetics beginning a ketogenic diet work with their health care provider so they can adjust their medication as needed while their glucose levels become lower and more stabilized.
When you’re eating carb-heavy high-glycemic foods, you experience a blood-glucose spike immediately after eating, followed by a subsequent drop in blood-glucose. On a ketogenic diet, you reduce your sugar and carbohydrate intake and naturally keep your blood glucose levels from rising and falling drastically. There will still be a small natural rise in blood glucose when you eat low-glycemic foods, but you won’t experience the high and low glucose level variations of a high-carbohydrate diet.
Plus, as we mentioned, by reducing your carbohydrates, you deprive your body of glucose stores, so your body begins using fats for fuel versus carbohydrates/glucose. This lowers insulin levels, because the body is no longer being tasked with managing so much sugar.
Even people with insulin resistance benefit from the ketogenic diet. With insulin resistance, your body doesn’t respond to insulin as it should. This often translates into higher blood-glucose levels and, over time, can lead to diabetes and increase your risk for heart disease. Studies following participants with diabetes who implemented a ketogenic diet show that participants saw drastic reductions in their fasting glucose levels (12).
6. Blood Pressure
Anyone with high blood pressure will appreciate the positive blood pressure control that results from a keto diet.
In studies following obese patients, those on a ketogenic diet experienced a more drastic reduction in their blood pressure than those on low-fat diets (13). Simultaneously, these same subjects following a keto diet had comparable weight-loss and triglycerides results as study subjects who followed a low-fat diet and received a weight-loss drug. The systolic blood pressure in the ketogenic group decreased (which is good for lowering high blood pressure), while it increased among the low-fat/diet-drug-medication participants.
7. Heart Health
A diet low in carbohydrates and higher in fats has been shown to drastically improve the biomarkers associated with heart disease.
In a recent study of a group of normal-weight, normolipidemic men (men with normal lipid amounts in their blood) who were put on a ketogenic diet for six weeks, 22 out of 26 biomarkers for cardiovascular disease risk improved significantly (14).
While some people experience a small increase in LDL cholesterol on a keto diet, it’s now suggested that LDL is not the “make it or break it” factor in determining heart health it was once believed to be. In fact, current research shows that LDL is a very small piece of the puzzle.
Now, it’s widely known that it’s the particle size of LDL that plays a larger role in determining heart health risks. Circulating LDL particles are actually quite diverse in size, and smaller, denser particles (which carry proportionately less triglyceride) are the ones associated with vascular damage and heart disease (15).
In fact, in a recent study of ketogenic diet participants where LDL increased, there was a shift in the size of the particles; average particles increased while the small, dense particles associated with vascular damage drastically decreased.
8. Brain Health
Ketones are a natural neuroprotective antioxidant that has been shown to prevent harmful reactive oxygen species from damaging the brain. Ketones have been shown to increase mitochondrial efficiency and production, which helps to protect brain cells. Finally a ketogenic diet has been shown to help regulate glutamate (a dominant neurotransmitter in our brain).
While much of the research around the ketogenic diet and the brain is in its infancy, the research that has been done is promising and shows a need for further exploration to fully understand the scope of benefits and clinical uses.
In one study, participants in the ketogenic diet reported a reduction in headache frequency and drug consumption (16). It was hypothesized that the success may be modulated by keto’s enhancement of brain mitochondrial metabolism and the inhibitory effects on neural inflammation and cortical spreading depression.
Who should do keto?
A ketogenic diet can be great for people who:
- Are overweight
- Have Type II diabetes
- Are looking to improve their metabolic health
It may be less suitable for elite athletes or those wishing to add large amounts of muscle or weight. It may also not be sustainable for some people’s lifestyles and preferences. Speak with your doctor about your eating plan and goals to decide if a keto eating plan is right for you.
Who should avoid keto?
The Keto diet should be avoided by people who:
- Are underweight
- Are facing an eating disorder
- Are below the age of 18
- Have diabetes and are on medication to help control it (ex. insulin, metformin, etc.)
- Are pregnant and/or lactating
- Are recovering from surgery