The ketogenic diet, commonly known as the keto diet, has emerged as a popular weight loss method, characterized by its high-fat, moderate-protein, and very low-carbohydrate composition. While it has gained considerable attention in recent years, understanding its implications, especially for beginners, is crucial. The keto diet may sound trendy, but it has been around for a while. It first surfaced in the 1920s. Originally, doctors recommended it to help with conditions like epilepsy and diabetes. But today, some people use the keto diet to lose weight.
Understanding the Keto Diet
The primary goal of the keto diet is to shift the body's primary fuel source from glucose to fat. For many Americans, carbs like breads, pasta, or potatoes make up more than 50% of their daily diet. Your body breaks down the glucose (sugars) found in carbs to fuel your body with energy. In a typical keto diet, your nutrition centers on fatty foods. They'll make up anywhere from 60% to 80% of your daily calories. Proteins make up 15% to 20%. Carbs are restricted to no more than 50 grams. This makes it quite a restrictive diet. This metabolic shift is achieved by drastically reducing carbohydrate intake, typically to no more than 50 grams per day, and increasing fat consumption to comprise 60% to 80% of daily calories, with protein making up the remaining 15% to 20%. When you're on the keto diet, you’re eating too few carbs to support your body's energy needs. As a result, your body turns to burning your stores of body fat to fuel your energy. When your body burns body fat for fuel, it produces ketones, substances made in your liver. Your body enters a metabolic state called "ketosis."
Types of Ketogenic Diets
If you're planning to start the keto diet, keep in mind that there are several types. Each one focuses on slight changes in the proportion of fat, protein, and carbs in your daily diet.
- Standard Ketogenic Diet (SKD): This is a very low-carb, moderate-protein, high-fat diet. It typically contains 70% fat, 20% protein, and only 10% carbs in your daily diet. The standard ketogenic diet (SKD) is characterized by a very low carbohydrate intake, moderate protein consumption, and a high proportion of fats.
- Cyclical Ketogenic Diet (CKD): This involves periods of higher-carb "refeeds," such as 5 ketogenic days followed by 2 high-carb days. The cyclical ketogenic diet (CKD) incorporates periods of higher carbohydrate intake, often referred to as "refeeds," strategically interspersed with ketogenic days.
- Targeted Ketogenic Diet (TKD): This diet allows you to add carbs around intense workouts. The targeted ketogenic diet (TKD) allows for the strategic addition of carbohydrates around periods of intense physical activity.
- High-Protein Ketogenic Diet (HPKD): It's similar to the SKD, but you can eat more protein. The ratio is usually 60% fat, 35% protein, and 5% carbs. The high-protein ketogenic diet (HPKD) is similar to the SKD but allows for a higher protein intake.
The standard and high-protein diets have been researched and studied the most. They're also the most common. The cyclical and targeted keto diets are recent additions and are mostly used by athletes or bodybuilders.
Historical and Current Applications
At first, the keto diet was primarily used as a way to help people with seizures. Over time, experts applied the benefits to several other health conditions, including:
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- Cognitive and memory improvement
- Type 2 diabetes
- Cancer such as glioblastoma
- Psychiatric disorders
- Alzheimer's disease
- Autism
- Obesity
The keto diet has been highly effective for certain conditions, especially type 2 diabetes. One study looked at the before-and-after keto diet results for 349 adults with type 2 diabetes over a period of 1 year. It reversed diabetes in about 60% of the participants. The keto diet also helped many of those in the study to lower their dependence on prescription insulin drugs.
Dietary Considerations and Planning
To start the keto diet, you may have to toss a few things out of your pantry and add certain high-fat food sources to include in your daily meals. Talk to your doctor or a nutritionist about what will work best for you. This is especially important if you have other dietary restrictions, such as being a vegan, vegetarian, or having certain food allergies. Experts can help you find alternatives or substitutes and come up with a meal plan that best suits your needs.
Before you start changing your meals, here are some questions you should consider or ask your doctor:
- Will the keto diet help manage certain health conditions?
- Do you need to lose weight?
- What are some of the side effects?
- Should you take or continue vitamins or supplements during the diet?
- How long should you stay on the keto diet?
- Should you exercise? If so, how much?
Keto-Friendly Foods
Some keto-friendly foods are:
- Nuts
- Seeds
- Full-fat dairy products
- Greek yogurt
- Non-starchy and fibrous vegetables
- Fatty oils
- Meat
- Fish
- Eggs
- Cottage cheese
- Coconut
For the 20 to 50 grams of carbs per day, choose non-starchy veggies like:
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- Broccoli
- Cauliflower
- Peppers
- Mushrooms
- Leafy greens
- Asparagus
- Green beans
Foods to Limit or Avoid
Foods to avoid or limit include starchy and high-carb foods like:
- Bread
- Baked goods
- Sugary sweets
- Pasta
- Rice
- Breakfast cereals
- Starchy vegetables like potatoes, sweet potatoes, corn, peas, and beans
- Fruits high in sugars
- Wine
- Beer, unless it's low-carb
In terms of acceptable drinks on the keto diet, you can opt for unsweetened coffee or tea. Cut down on how much alcohol you drink. If you drink alcohol, choose low-carb liquors like tequila or vodka and use soda water as a mixer.
Keto-Friendly Snacks
Keto-friendly snacks are a good balance of healthy fats and moderate protein with low-carb content. You can make some at home or use store-bought versions.
This includes snacks such as:
- Brazil nuts
- Walnuts
- Hazelnuts
- Peanuts
- Coconut yogurt
- Guacamole
- Cheese
- Canned tuna
- Meat jerky
- Olives
- Pork rinds
- Seaweed snacks
- Hard-boiled eggs
- Jicama (low-carb root vegetable).
These snacks can help you manage your hunger between meals and stick to staying in ketosis in the long term.
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Potential Side Effects and Considerations
While research shows that the keto diet helps some people lose weight or manage health conditions, the restrictive diet isn't a good idea for everyone. It may be harmful if you follow the diet incorrectly or without proper supervision. The keto diet also affects each person differently. While some people can transition easily to the dietary changes, others may find that their body takes longer to adjust to the sudden changes. It's important to get your cholesterol checked regularly. The keto diet may decrease cholesterol for some people, but it may increase cholesterol for others. The low-carb part of the diet may have long-term consequences for some people. For many, cutting out carbs so suddenly and drastically can lead to what many popularly call the "keto flu."
The "Keto Flu"
You may get flu-like symptoms as your body navigates switching from burning glucose to fat for energy.
Symptoms of keto flu include:
- Stomach aches or pains
- Nausea
- Dizziness
- Sugar cravings
- Cramping
- Muscle soreness
- Feeling cranky
- Diarrhea or constipation
- Trouble falling asleep or staying asleep
- Poor focus and concentration
- Brain fog
Usually the symptoms of keto flu kick in a day or two after you cut carbs from your daily diet. They may last up to a week or less, but in severe cases, they could last up to a month. If the symptoms are severe or persist, see your doctor or stop the diet. To lessen the chances of getting the keto flu, start the diet slowly, stay hydrated, do only light exercises, and get plenty of rest as your body gets used to your new meal plan.
Another pitfall that experts warn about is that there are too many types of keto diet and it's easy to do it incorrectly. You may end up eating too many saturated fats instead of healthy fats that can put you at risk for high levels of bad cholesterol and heart disease. You may also not reach ketosis if you don't follow the diet properly.
Gut Health and Other Potential Side Effects
The keto diet can also affect your gut health. That's because the diet mostly requires you to cut out nutrient-dense and fiber-rich foods like legumes, whole grains, starchy vegetables, and fruits. The studies on keto's effects on gut health are conflicting. There needs to be more research done on this topic.
Other side effects can include:
- Low bone density and bone fractures
- Constipation
- High cholesterol
- Kidney stones
- Slower growth than typical
- Fatigue
Real-World Results: 60-Day Keto Diet Challenge
Many individuals have reported significant positive changes after adhering to a keto diet for 60 days.
Here are some real-world results from participants in a 60-Day KetoDiet Challenge:
- One participant went from 214 lbs to 195.8 lbs, incorporating clean eating, low-carb recipes, water consumption, and regular exercise.
- Another participant dropped from 255 lbs to 230.8 lbs, a loss of 24.2 pounds.
- One individual reported a weight loss of 8.8 kg, going from size 50 to size 46/48.
- Another participant lost 11.2 pounds, reaching 149.4 pounds, with increased energy levels.
- A 56-year-old participant lost 4 pounds during the challenge, adding to a previous loss of 33 pounds, and experienced improvements in eyesight, blood pressure, endometriosis pain, arthritis, and energy levels.
- One participant, nearly seventy years old with Chronic Fatigue Syndrome (CFS), reported improved muscle tone and healthier skin despite limited exercise.
- Another individual lost 5.2 kgs and over 7 cm all over, with improved well-being.
- One participant lost 11 lbs in the last 60 days.
- One participant weighed in on day 1 of the keto challenge at 295 lbs, a size 20 pant and 2X shirt. In day 60, I have weighed in at 273.8 lbs, size 16 pant and XL shirt.
These experiences highlight the potential for weight loss, increased energy, and improvements in various health markers.
Success Stories
- Michael Searls: Lost 100 Pounds. He was in the store buying pants-he knew he'd put on a few pounds, and figured he was now too big for his usual 32 or 34 waist size. After he tried sliding on a pair of 38's, however, he realized they were still nowhere close to fitting. "I panicked that day. I ended up putting on a size 46, and I remember being in the fitting room just looking at myself with tears in my eyes, not believing I was that size," he says.
- Matt Clemente: Lost 200 Pounds. Matt Clemente was in his late thirties and weighed 417 pounds. Over the next two years, Clemente would lose over 200 pounds, pack on muscle, and reach a stocky 207 pounds, running Spartan races and doing CrossFit.
- Andrew Kim: Lost 90 Pounds. As a kid, Kam noticed he was always bigger than other kids. Kam’s weight issues compounded during freshman year of college, when his mother died after battling cancer.
- Ethan Spiezer: Lost 130 Pounds. When his weight peaked in his mid-thirties, Spiezer estimates that he weighed between 410 and 420 pounds. "I would be sad that I was so big and eat as a result, which would make me feel worse. It became a vicious cycle."The turning point proved to be a photo that a bystander took of Spiezer and his son during a boat tour while on vacation in San Diego. Spiezer decided that day to commit to eating healthier and being more active, and has since undergone a dramatic weight loss transformation, dropping more than 135 pounds in less than year.
- Jeremiah Peterson: Lost 92 Pounds. As a kid in the 1980s, Jeremiah Peterson made the commitment to get fit - not just for his looks, but to fight off the bullies, too.
- Tyler Segraves: Lost 141 Pounds. But when his weight hit 335 pounds, he knew something had to be done.
- David Myers: Lost 130 Pounds. Myers, 27, who works as a high school math teacher in Turlock, California, says the low point-as is so often the case-arrived when Myers saw pictures of himself, and realized the truth about how much he'd let himself go. At the time, he weighed nearly 360 pounds, and it suddenly became clear that the time to start eating better and exercising was long overdue.
- Antonio Gutierrez: Lost 100 Pounds. Antonio Gutierrez still remembers the day he came home from the amusement park in tears. He'd been about to board a rollercoaster, but when he went to sit down, the safety harness wouldn’t close.
- Tim Kirkwood: Lost 250 Pounds. Coupled with a sedentary job, Kirkwood weighed 550 pounds at age 36. Kirkwood lost almost 250 pounds thanks to keto and intermittent fasting.
- Graham Winder: Lost 10 Percent Body Fat. After the birth of his child, Graham Winder found himself hitting the gym less. Realizing it was time to make a change, Winder gave up carbohydrates from grains, pasta, and beer. He also took up the keto diet. He incorporated a rigorous workout routine with the help of a personal training studio.
- Eric Clarke: Lost 190 Pounds. Clarke reached 415 pounds in his 30s and decided to change his relationship with food. He opted for keto because he enjoyed the low-carb, high-fat plan, which was key to his success.
- Kevin Ozee: Lost 130 Pounds. At the time Ozee weighed 345 pounds. Now, he's 213 pounds, thanks to the Keto Diet.
Keto Diet: A Month-by-Month Breakdown
Week 1: Rapid Water Weight Loss
Your first week delivers the most dramatic scale changes, but here's the reality check-most of this initial loss is water weight, not fat. When you slash carbs, your body depletes glycogen stores in muscles and liver. Since glycogen binds to water at roughly a 3:1 ratio, releasing these stores creates rapid weight loss.
Week 2: Keto Flu
You'll likely experience the infamous "keto flu" during days 2-7. Harvard Health Publishing reports symptoms including headache, brain fog, fatigue, irritability, nausea, difficulty sleeping, and constipation. You're also fighting decades of carb-centric eating habits while dealing with withdrawal-like symptoms from sugar and processed foods. Studies analyzing online user reports found that about one-third of keto dieters experience flu-like symptoms. Medical News Today recommends consuming plenty of fluids and electrolytes to help manage symptoms.
Week 3: Transition to Ketosis
With glycogen depleted, your body starts breaking down stored fat for energy. Weight loss slows to a more sustainable 1-2 pounds as you enter ketosis. This transition period marks when genuine fat oxidation accelerates as your liver begins producing ketones more efficiently. The keto flu typically subsides, and energy levels begin stabilizing.
Week 4: Metabolic Adaptation
Many people describe week three as their "keto breakthrough." Fat loss continues at 1-2 pounds while energy and focus peak. By week three, many people have achieved full ketosis and metabolic flexibility. Workouts feel strong again, mental sharpness improves, and hunger significantly decreases. Weight loss may slow as your body adapts to its new fuel source. This isn't a failure-it's biology. EatingWell's 30-day keto experiment documented how metabolic adaptation causes weight loss plateaus. As you lose weight, your body's total daily energy needs naturally decrease, which can slow the rate of loss.
Beyond the Scale: Measuring Progress
After 30 days, your changes extend far beyond the scale. The bathroom scale tells only part of your story. While scales measure total weight, body composition provides a more accurate picture of your progress. Track waist, hips, chest, arms, and thighs weekly. Take front, side, and back photos in consistent lighting and clothing. Note sleep quality, workout performance, mental clarity, and hunger levels.
Maintaining Muscle Mass
Studies on ketogenic diets and physical performance demonstrate that when protein intake remains adequate (around 1.6g per kg of lean body mass) and resistance training continues, muscle preservation is excellent during keto adaptation. One of keto's most significant benefits appears in visceral fat reduction-the dangerous fat surrounding your organs. For the most accurate picture of your body composition changes, a DEXA scan provides precise measurements of fat mass, lean tissue, and bone density that bathroom scales simply can't deliver.