Low-carb diets have been around for decades. There is frequent debate as to whether they are healthy, safe and effective. The ketogenic diet is one low-carb diet that has recently seen a rise in popularity. It’s worth discussing keto diet basics- the scientific merits of this diet plan as well as potential side effects and risks.

With the ketogenic diet, keto diet for short, you will take in very few carbohydrates while consuming high-fat, high-protein foods. This change will prompt the body to burn its own fat as an alternative source of energy. This process is called ketosis.

Some advocates of the keto diet will describe it as a way to turn the body into a fat-burning machine. However, it is important to recognize exactly what the diet requires to be an effective weight loss measure.

When the keto diet is followed correctly, it can be a powerful weight-loss solution that may also aid in managing conditions. However, the keto diet is not right for everyone. You should think about your own health concerns and talk to your doctor before starting this diet.

What is the keto diet? Here are some keto diet basics.

Though the keto diet has only recently become trendy, it has been around for a long time. It was originally developed as a means of treating seizures in epileptic children. The diet has also been regularly recommended as part of treatment and management for several different health conditions, including cancer, Alzheimer’s disease, Parkinson’s disease and polycystic ovary syndrome.

Keto diet basics: Foods

On a ketogenic diet, the goal is to minimize carbohydrate intake while maintaining the right ratio of fat to protein. Ideally, carb intake on the keto diet should be about 5 percent of what a person eats. Seventy-five percent should be fat and the remaining 20 percent should be protein. To achieve this balance, you must primarily eat:

  • Red meat
  • Pork and pork products, including bacon and sausage
  • Fatty fish, including salmon, anchovies, and sardines
  • Eggs (yolks included)
  • Full fat cream and butter
  • Unprocessed cheese
  • Nuts and seeds
  • Olive oil, avocado oil, and coconut oil
  • Avocados
  • Leafy greens
  • Low-carb vegetables
  • Salt, herbs, and spices

Keto diet basics: The rules

  • Any processed food should be consumed in limited quantities.
  • Whole, single-source foods will be the healthiest low-carb options.
  • It is generally recommended to seek out free-range, grass-fed and organic options when following the keto diet.
  • Foods that will need to be significantly restricted on the keto diet include:
    • Sugary foods and beverages.
    • Polyunsaturated fat, found in many vegetable oils, mayonnaise and fried foods
    • Alcohol
    • Starches and grains, including cereal, pasta, bread, oats, rice and wheat
    • Most fruits
    • Beans
    • Low-fat products
    • Sugar-free diet foods
    • Root vegetables, including potatoes, beets and yams

Not all of the foods on the restricted list are necessarily unhealthy on their own. However, they are problematic when following the ketogenic diet because of their carbohydrate content.

Because there is such a long and varied list of foods to avoid and restrict on the keto diet, you may have to go through a period of adjustment when starting out.

What’s the science behind the keto diet?

Let’s use a parallel to simplify the ketosis process. Think of your body as a hybrid car. While the car usually gets its power from gasoline, our bodies get power from the food we eat. We get a great deal of the energy we use from carbohydrates found in many of the foods we consume regularly. However, we can also get energy from fat cells, which store energy in the body. It is essentially the same as when a hybrid car shifts into electric mode and uses its secondary battery instead of external fuel for power.

The ketogenic diet encourages your body to use more of its own stored energy by reducing your carbohydrate intake. This way your body won’t get enough raw energy from the food you eat alone. This will kick-start the ketosis process of breaking down fat cells so you can use the energy within them to power your body through regular activities.

A closer look at the keto process

  • Breaking down your body’s fat cells: Fat cells accumulate as excess energy after your body uses the energy it requires from the food you eat. Unfortunately, modern diets have emphasized large portions, high concentrations of sugars and simple carbohydrates, and more bad fats, such as trans fats and polyunsaturated fats. To lose weight, you must alter your diet so you are consuming less energy than your body uses, causing your body to access stored energy in your fat cells and burn excess fat.
  • Why you can consume high-calorie foods in the keto diet: When we talk about using more energy than you take in, it’s tempting to look exclusively at calories. After all, calories tell us how much energy is in a given type of food. However, the calorie count does not tell the whole story. Just think about how different 100 calories of celery are from 100 calories of cheese and how both of those are different from 100 calories of chocolate cake. Food contains a broad array of nutrients, which are broken down in different ways to produce energy. Carbohydrates break down into glycogen, which is what many tissues in the body use as fuel. That is why you can eat high-fat, high-calorie foods on the ketogenic diet—provided that you are significantly limiting your intake of sugar and other carbohydrates.
Ketosis as starvation hacking

If your body does not have sufficient carbohydrate energy, it will not have enough insulin to convert sugar to glucose to be used as fuel in the body. This causes the body to burn fat, but your fat cells do not contain readily accessible energy. Fat must be broken down by the liver to create ketone bodies, which are organic compounds that the brain is able to use as an energy source. When your body is creating ketone bodies for energy, it is in a state called ketosis.

Your body is able go into ketosis because humans evolved as a nomadic species, which meant that food sources were not always plentiful. The body needed to have a way of storing energy for later use so that it would not be immediately shut down by starvation. In a basic sense, you can think of ketosis induced by a low-carb diet as starvation hacking for the body. It will trick the body into using its own fat cells for energy, even though you will still be consuming plenty of food following a ketogenic diet.

How will you know you’re in a state of ketosis?

Ketosis is the state that the body enters when it is generating ketones in the liver to produce usable energy. It is also a normal part of the metabolic process and will occur whenever you go a long time without eating and do not have energy remaining from the food you’ve eaten. As ketosis continues, your body begins to use ketones more efficiently. Periods of fasting that last for several days may result in increased mental clarity and focus.

By following the keto diet basics and consuming fewer carbohydrates, your body will be able to enter sustained ketosis. For most people, this will mean eating about 50 grams of carbohydrates per day—about as much as is in one cup of rice. However, some people will need to eat as few as 20 grams of carbs per day to maintain ketosis. This is why it is so important to know the exact nutrition facts for everything you eat on the keto diet—a small misstep could easily throw you off. This is pretty much keto diet basics 101.

You also need to consider more than just carbs. The fat-to-protein balance is important as well. If you eat too much protein, this can spike your insulin levels and drive down ketone generation. Exercise is yet another way to end ketosis, as longer exercise sessions or high-impact exercise might put higher energy demands on the body.

Keto Diet Side Effects

Because ketosis is not a static state and ketone production can easily fluctuate, it’s important to understand how to identify when you have achieved ketosis. This is especially true as you are starting out on the diet and need to know when you may be knocked out of a ketogenic range. Ketones are organic compounds that have distinctive odors and colors that may make themselves known as they escape the body. When ketones are produced, some may be expelled through the urine and through the lungs. This can cause keto diet side effects like:

  • Keto breath. Dieters will often report a fruity or metallic taste and strange mouthfeel as ketone compounds are expelled through the mouth when exhaling.
  • Off-smelling urine. Just as ketones can cause bad breath, they may cause an odor in urine as well. Some people also notice changes to the color of their urine.

Ketosis can lead to changes in your physical and mental state:

  • Appetite suppression. You may be surprised by how seldom you become hungry between meals as your body begins to sustain ketosis.
  • Lack of afternoon decline. Ketones can provide a more sustained source of energy for the brain, as your body can constantly break down fat in ketosis. In contrast, there is a cyclical metabolic process that occurs when you are digesting carbohydrates. With the more sustained energy provided by ketones, you may function without a typical afternoon slump once you enter ketosis.
  • Digestive discomfort. Substantial changes in your diet to shift toward ketogenic eating can cause you to have diarrhea, constipation and other discomforts as your body adjusts. While these signs alone will not necessarily indicate ketosis, they may signal that you are on track with your diet. Consuming more fiber as well as magnesium supplements may help ease these symptoms.

If you are following a ketogenic diet and are consistently feeling tired, weak or fatigued, then it is likely that you are not in full ketosis. To address this, you may need to follow a stricter keto meal plan or even consider taking supplements to ensure that your body is utilizing ketones effectively.

You may also want to measure your ketone levels with at-home blood or urine testing kits. The keto testing strips can give you a more definitive measure of whether you are in full ketosis.

What are the long-term effects of ketosis on the body?

One interesting change with the keto diet is that, over time, ketosis becomes a more efficient process. This means the body is better adjusted to relying on ketones for a significant ratio of its energy and fewer byproducts will be released in the process. That means you’ll have fewer of the initial negative side effects of ketosis, like keto breath and fatigue. You may also notice more constant mental focus and alertness, and experience fewer food cravings and less hunger between meals.

In addition, a long-term state of ketosis will cause the body to maintain more stable insulin levels, since insulin won’t spike and fall in response to digesting sugars and carbs. This can have a significant impact on diabetes as well as polycystic ovary syndrome (POS) — both of these conditions are linked to insulin resistance.

Weight loss through ketosis is a steady, ongoing process. You should not expect to lose a large amount of weight at once, but you should expect to see consistent losses on the scale. Initially, your weight loss can be attributed to shedding stored carbs and water weight. This will be a rapid drop, but then you can expect to lose about 1-2 pounds per week. Studies have indicated that fat loss with the ketogenic diet is more significant than with low-fat, low-calorie diet plans. That means that more of the weight you lose overall is from fat, rather than from muscle and other lean tissues.

How do you handle the initial keto diet side effects?

Though you may eventually start to feel more focused and energized on the keto diet, you might feel adverse keto diet side effects at first, including digestive discomfort, insomnia and decreased exercise performance. There may also be a general sense of fatigue in the first weeks of the keto diet. These symptoms are often referred to as keto flu or low-carb flu. They occur because the ketogenic diet will alter the water and mineral balance of your body, so you may easily become dehydrated.

Keto diet side effects will subside after a few weeks for most people, but you can take steps to minimize keto flu symptoms as you start following this diet program. First, be sure to drink plenty of water throughout each day. Second, increase your salt intake to restore your electrolytes. Third, avoid strenuous exercise and be sure that you are eating enough.

You might even spend the first few weeks following a standard low-carb diet before more strictly reducing carbs. That way your body can adjust more smoothly to a higher fat diet.  

What are the pros and cons of the ketogenic diet?

There are many merits to the ketogenic diet, and, for many people, it is a highly effective way to lose weight. Still, there are drawbacks and potential risks to consider, so you should weigh all the pros and cons before deciding if the keto diet is right for you.

Pros:

  • Multiple scientific studies support weight loss and significant fat reduction.
  • Potential management of dangerous health conditions, including type 2 diabetes, heart disease and polycystic ovary syndrome
  • More opportunities for support and food choices as the keto diet becomes more popular.
  • Reduction of food cravings and suppressed appetite over time for more consistent long-term weight loss.

Cons:

  • High consumption of animal fats and meats, including processed meats like bacon, may raise the risk of certain cancers.
  • Difficulty finding appropriate food choices while dining out.
  • High sodium consumption can be risky for individuals with high blood pressure.
  • A tough period of adjustment with the possibility of “keto flu” when starting the ketogenic diet.

Dangers of the keto diet

Should you go on this diet? The answer will depend on your specific health and weight loss need. Don’t get started without consulting your primary physician first so you can fully understand the keto diet basics and how the keto diet realtes to your specific health.

However, if you are overweight, diabetic and struggling with your health as a result of obesity, the keto diet may be a suitable choice.

It is not an appropriate diet plan if you are looking to gain more muscle or you want to sustain a very active lifestyle. It is also not fit for those who are taking medication to manage diabetes or insulin resistance, as excess ketones can be a health risk for people with uncontrolled diabetes.

People with high blood pressure should avoid the ketogenic diet due to the high sodium content that’s consumed following the program. If you don’t have any of these disqualifying factors, you may have success with the keto diet and a long-term commitment to a low-carb lifestyle. The success of this diet is well-researched and established, distinguishing it from many other diet programs out there.

Reference materials on the keto diet: