The ketogenic (keto) diet is a revolutionary nutritional approach designed to transform you from a sugar burner into a fat burner. The diet has been in use since the early 1920s for treating a wide range of conditions. But in the past several years, it's gaining momentum as a weight loss diet.
But how exactly does a high-fat diet like keto make people lose weight? Although seemingly counterintuitive, this fatty diet does truly help with weight loss as evident by countless testimonials and scientific research. It all has to do with ketosis – a metabolic switch that takes place when you go keto.
Here we explain more about how people use the keto diet to lose weight, how ketosis helps with this, and what metabolic changes take place when you go keto. Knowing all of this will help you understand how keto works for weight loss.
The keto diet is a low-carb, moderate-protein, and high-fat diet. A group of scientists designed the diet in the 1920s to treat epilepsy. Decades later, researchers began looking into keto as a treatment for overweight and obesity but also for diabetes, brain injury, and even cancer.
On a keto diet, between 70 and 80% of your calories should come from fat while only 5 to 10% should come from carbohydrates. In comparison, international recommendations state that 40-75% of your calories need to come from carbs .
This means that keto is the exact opposite of what people associate with healthy eating. But what many don't know is that this diet is not classified as a fad and that this unusual approach to nutrition is designed with a specific purpose in mind – ketosis.
Ketosis is a metabolic state where the majority of your body's energy comes from ketones. Ketones are acidic molecules the liver makes to replace glucose in the absence of carbohydrates. These molecules include the following three:
The Goal of the Ketogenic Diet
The primary goal of the ketogenic diet is ketosis, but the ultimate goal is keto adaptation. Keto adaptation, also called fat adaptation, is when your body has adapted to burning fat for fuel. Most people start keto not being fat adapted and are considered "metabolically inflexible."
You see, your body normally relies on glucose for fuel, and some organs are completely dependent on it (e.g. the brain). That's why evolution designed ketones as an alternative fuel. You can think of ketones as standby generators.
Your body makes ketones from fatty acids. Greater ketone production can happen during starvation or long periods of fasting. Your body also makes a small number of ketones during an overnight fast and after vigorous exercising.
The ketogenic diet is based on this knowledge of how the body works is times of starvation or prolonged fasting. Researchers eventually discovered that you don't need to starve yourself to get into ketosis; cutting back on carbs produces the same results, i.e. leads to nutritional ketosis .
How Ketosis Leads to Weight Loss
When you are in a state of ketosis, your body is burning more fat than when you are in your usual sugar-burning mode. This is the main reason keto leads to weight loss.
Furthermore, in ketosis, the body burns either the fat you eat, or the fat stored in adipose tissue. Which fat gets burned depends on your daily calorie intake.
For example, if you eat fewer calories than needed to maintain your current weight – aka enter a calorie deficit – your body burns fat stores in order to compensate for this deficit. In comparison, if the fat you are eating contains enough calories to sustain your current weight, the body will not feel there is a need to burn precious fat stores.
The reason the body turns a portion of the burned fat into ketones is because many cells in your body cannot use fatty acids to make energy. Brain cells, especially, need either glucose or ketones for energy.
Bottom line is that ketosis together with a calorie deficit forces your body to burn its own fat stores. Without that calorie deficit, ketosis is unlikely to lead to weight loss as your body is burning only fat from food and not fat from adipose tissue.
Should You Count Calories on Keto?
You probably heard that you don't need to count calories on keto. And this is true to some extent. Most keto dieters don't really count calories. And yet, a calorie deficit is essential to losing weight on a keto diet, so what gives?
Well, the ketogenic diet has a natural appetite suppressing effect so counting calories isn't necessary . Here are some explanations why this is so:
Studies show that being in ketosis suppresses the levels of hunger hormones, most notably ghrelin . Normally, weight loss leads to a rise in hunger hormones, but this is not the case when you're in ketosis.
On keto, you're eating more fat and protein than carbs. Protein is the most satiating macronutrient of the three while fat is somewhere in the middle. Research shows than unsaturated fatty acids have the most appetite-suppressing effect .
Sugary foods cause sharp sugar spikes and crashes which leaves you feeling hungry. The keto diet eliminates this problem completely.
Cholecystokinin is a peptide hormone that stimulates the release of bile and digestive enzymes for the digestion of fat and protein. Studies show that this hormone acts as a hunger suppressant .
Because keto suppresses your appetite significantly, your chances of overeating on keto are low. In fact, many keto dieters feel like they're eating too little on this diet.
Still, if you want to make sure your calorie intake is low enough for weight loss, do keep track of your daily calories. Use our Keto Calculator to see how much of each macro you need to eat to achieve a calorie deficit.
Ketosis and Metabolic Changes
Ketosis is in itself a major metabolic shift. Being in ketosis means your body has made the switch from burning sugar (glucose) for energy to burning fat for energy. However, many other metabolic changes take place on a keto diet and that also help with weight loss:
Research shows that keto boosts insulin sensitivity . Greater insulin sensitivity means that your body can efficiently use food for energy. This alone is important for normal metabolism functioning and is essential in preventing type II diabetes and excess weight gain.
Triglycerides are the most common type of fat in the human body. Having excess triglycerides in the blood is a strong risk factor for cardiovascular disease, heart attacks, and stroke . Keto helps lower triglyceride levels from by almost 30 mg/dL after just a couple of weeks .
The resting metabolic rate (RMR) is the rate at which your body burns calories at rest. The RMR is low in people who are inactive, overweight, or suffer metabolic disorders. That's a problem because a healthy RMR helps you sustain a healthy weight. Keto helps boost or preserve your RMR which is essential for steady weight loss .
All these metabolic changes together with ketosis not only help you lose weight and keep it off, but they also help improve your overall health. Metabolic disorders are the leading drivers of dangerous conditions like heart disease, diabetes, and even cancer. Keto will keep you healthy by keeping these diseases at bay.
How Much Weight Will I Lose?
Research shows that people can lose up to 33 pounds after 5 months on a keto diet . However, the actual rate of weight loss on keto varies from one person to the next. Keep in mind that the weight loss rates described below are an estimated average.
On a ketogenic diet, you will experience three phases of weight loss:
- Water weight loss
- Rapid weight loss
- Slow weight loss
During the first week of a ketogenic diet, most people notice a drop between 2 and 10 pounds. Most of this is water weight, however. The sharp loss of fluids on keto is a result of:
a) Glycogen depletion
Your muscles and liver store glucose in the form of glycogen which is 3-4 parts water. Because you are not eating carbs on a keto diet, your body starts spending these glycogen stores rapidly. And with that rapid loss of glycogen, you also lose water bound to it.
b) Electrolyte imbalances
Electrolytes are substances that conduct electrical activity in your body. These also balance out fluids in tissue. When you lose a lot of water in the first week on keto, you also lose some electrolytes leading to imbalances which can affect your body's ability to retain water.
After about a week, your body will start becoming keto adapted. During this period, you will finally start burning fat and utilizing ketones. From weeks 2 to 12, you can expect a steady weight loss of 1-2 pounds per week.
However, after 12 weeks are over, many ketoers notice their weight loss beginning to stall, i.e. they enter a keto plateau. This is completely normal and not a sign that something is wrong with your diet or your body.
There are ways you can tweak your keto diet to break through these plateaus. Once you do that, you can expect a slow but steady weight loss. This happens as you start to reach your goal weight and the slowing down is your body's attempt to preserve fat. You can read more about the keto plateau here.
According to the WHO, almost 40% of adults worldwide are overweight while 13% are obese . That's a lot of people struggling with excess weight, and the majority have tried to lose weight at some point.
The problem is not that classic weight-loss diets don't work, it's that they're not good for long-term success. That’s because these diets, which are usually low-fat and low-calorie diets, increase hunger hormone levels, slow-down metabolism, and make your overcompensate after initial weight loss.
Keto is different. The keto diet gets to the root cause of weight gain and overeating. The diet has an appetite suppressing effect; forces your body burn fat, and it boosts your metabolic health. As long as you stick to the diet, your chances of regaining the weight are pretty low.
Even studies show that obese patients can follow keto safely for up to a year with great success . One recent study involving 12 obese people found that the subjects lost an astounding 45 pounds and kept the weight off even after increasing their calorie intake . Researchers believe this success was due to keto improving the participants' RMR.
You don't have to exercise to lose weight on a keto diet. However, adding an exercise regimen to your keto lifestyle will lead you to greater success. Besides, exercising is good for your health and helps you get the body you're after.
The best type of exercise for weight loss include:
Endurance training elevates heart rate over a long period of time. The goal of endurance training is to increase your endurance. Most athletes practice endurance training weeks before competitions. Research shows endurance training to be effective in boosting fat burning .
Resistance training strengthens your muscles. In resistance training, your muscles contract against an external force or weight. Weight lifting is an example of resistance training. Resistance training does not increase fat burning per se, but it does boost muscle mass which helps with weight loss.
Also known as "cardio," aerobic training increases heart and breathing rate which helps pump oxygenated blood to working muscles. Examples of aerobic training include running, cycling, hiking, and kickboxing. A study on 141 overweight participants found that aerobic training even without calorie reduction causes weight loss .
Ideally, you should include different types of training methods to increase endurance, muscle strength, and fat burning. For good health, 30 minutes of physical activity daily is a must. But for weight loss, up to 300 minutes a week is ideal.
Many ketoers use intermittent fasting as a means to further boost weight loss. But some also use it to get into ketosis faster. Adding it to your keto journey can also help break through weight-loss plateaus.
Intermittent fasting involves fasting and feeding during defined periods of time. For example, you skip breakfast and avoid food for the next 12 hours. When this period is up, you eat within the next 4 hours which is called the "feeding window."
The reason intermittent fasting works for weight loss is because it allows you to eat less. Instead of having 3 or 4 meals a day, you eat one meal within your feeding window. It's important that this meal be a moderate-calorie meal to avoid overeating. However, this is highly unlikely to happen because keto reduces your appetite and because keto meals are rich in satisfying fats and protein.
And as for the effectiveness of intermittent fasting in weight loss, studies show that it does improve metabolic health . Intermittent fasting also boosts ketone production during the fasting period and increases longevity by upregulating autophagy. Autophagy is your body's cell recycling system that helps with cell renewal and regeneration.
How to Use the Keto Diet to Lose Weight
If you're curious about the practical details of losing weight with keto, here we'll tell you what steps you need to take to make that happen.
Step I – Creating a Meal Plan
The keto diet is strict when it comes to what you are allowed and not allowed to eat in order to reach ketosis and stay there. That's why creating a meal plan is absolutely necessary. To start creating your meal plan, you first need a shopping list. Here are some keto staples to start adding to your pantry:
- Fats– Olive oil, Coconut oil, Butter, Lard, and high-oleic sunflower oil are common keto staples. These sources of fat are unrefined and come with unique health benefits depending on their fatty acid profile.
- Proteins – Fatty cuts of meat, poultry, eggs, high-fat dairy, fish, tofu, nuts, and seeds all contain fats and proteins to meet your need for these nutrients on keto.
- Low-carb vegetables – Most leafy greens are low in carbs. Other low-carb veggies include eggplants, cauliflower, broccoli, peppers, artichokes, zucchini, and celery stalks.
- Low-carb fruit – Berries are allowed on a keto diet in small amounts. Other low-carb fruits include rhubarb and lemon.
- Flour substitutes – Almond, hazelnut, and coconut flours replace wheat flour on a keto diet. You can also use chickpea flour in small amounts.
- Milk substitutes – Nut milk like almond and coconut milk replace milk on a keto diet as dairy milk contains lactose which is a type of sugar. Soy milk is not a good alternative to dairy due to its carb content.
- Non-nutritive sweeteners – Stevia, erythritol, and monk fruit are popular keto sweeteners.
- Herbs and spices – Most herbs and spices are low-enough in carbs to be keto-approved. These are also used in small amounts so there's no need to worry about their carb content.
Now that you have your ingredients ready, take a look at our Recipes Section to get inspired. There, you will find over 300 keto recipes. Note down the recipes you have in plan for the next couple of days or a week. That way, you'll ensure you're eating three keto meals a day to enter ketosis.
When creating your plan, you'll need to consider the macros and calories for each meal. Make sure your daily calorie intake is low enough to cause weight loss. A deficit of 15-30% is more than enough for the time being. For example, if you usually eat 2,000 calories a day, eating 1400 – 1700 calories will make you lose weight.
Step II – Prepare for What's Ahead
When you first go keto, chances are you'll experience the "keto flu." The keto flu is side effect of glycogen depletion and electrolyte imbalances that happen in the first week or two of going keto. Symptoms include headaches, muscle pains, nausea, fatigue, and brain fog.
To treat and even prevent the keto flu, you need to drink enough fluids and take electrolytes. Sugar-free sports drinks help as do bone broth and bouillon cubes.
Besides the keto flu, you may also have to fight carb cravings. Carb withdrawal is a real thing. It causes you to experience strong cravings for carb-rich foods. Studies show that our brain's reward system is activated when we eat sweet-tasting, carb-rich food .
Step III – Track Your Progress
To stay motivated on a keto diet, it's important to track your progress. Many keto dieters like to measure their ketone levels early in their keto diet to see if they're on the right track. Ketone Urine Test Strips are a convenient and affordable way to see if you are in ketosis.
However, once you become fully keto-adapted, you want to keep track of your weight loss. To do that, you can use body fat calipers or simple tape measures. But don't be a slave to the scale, though. The numbers on the scale aren't an accurate representation of fat loss.
You see, when you burn fat and gain muscle simultaneously, the numbers on the scale don't go down in a linear pattern. Weight also tends to fluctuate depending on how much water your body stores at a given time. This is especially true for women who experience fluctuations in water weight through their monthly cycle.
Step IV – Tackle Plateaus
Because weight loss is not a linear process, you will experience stalling and plateaus after weeks of steady weight loss. Plateaus happens because your body is making metabolic adaptations to preserve what's left of body fat. Stalling on keto can also happen because you are eating too many calories.
To tackle stalling and get to your goal weight, you may need to:
1. Lower your calorie intake & upgrade your workout routine
When it comes to weight loss, at the most basic level it really all boils down to calories in and calories out. When you start keto, you lower your calorie intake and lose a couple of pounds. Then, this lower amount of calories is sufficient to maintain your current weight.
That's why you may either want to lower your calorie intake further, but not too much to avoid nutrient deficiencies. We don't recommend going below 1,300 calories for anyone.
Instead what you should do is increase the intensity or duration of your workout routines. Then, once you've reached your goal weight, continue eating a steady amount of 2,000 – 2,500 calories and stay active to keep the weight off.
2. Take keto supplements
Keto supplements are a great weight-loss tool. MCT oil, exogenous ketones, and collagen peptides are examples of keto supplements that dieters use to get through stubborn stalling.
MCT oil helps suppress your appetite and at the same time boost ketone production. Exogenous ketones give you energy for workouts without the need for carb refueling. And collagen peptides keep you feeling full while supporting muscle strength.
Although originally designed to treat epilepsy, most people today use the keto diet to lose weight. The diet is designed to boost fat burning for the sake of greater ketone production. When combined with lower calorie intake, the diet inevitably leads to weight loss.
The diet takes a unique approach to fat burning and research shows it is safe and effective in the long run. If you want to use the keto diet to lose weight, we suggest taking our Ketocademy course. It will help you learn everything you need about the keto diet to lose weight in under 3 hours.