Locations:
Search IconSearch

What 30 Days on the Keto Diet Feels Like

How the ketogenic diet works, getting past the 'keto flu'

Weight Loss: What 30 Days on the Keto Diet Felt Like

I never recommend diets I haven’t tried. Since so many patients ask me about the ketogenic diet, I decided to dive into it with both carb-loving feet — for 30 days.

Advertisement

Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy

What is the Keto Diet?

On this diet, 70 to 80% of your calories come from fat, and about 5% come from carbohydrates (that’s around 25 net carbs after subtracting fiber from total carbs). Moderate amounts of protein account for the remaining calories.

A big change

The huge drop in carbs left me famished that first week. To limit myself to 25 net carbs, I had to replace traditional carbs with:

  • Tree nuts (½ cup of macadamia nuts is 2 grams).
  • Vegetables (1 cup of broccoli is 4 grams).
  • Pure coconut chips (a 1-ounce serving is 5 grams).

Here’s what daily meals typically looked like:

Breakfast: A protein smoothie, or eggs with a side of avocado (taking care with egg whites, which increase protein).
Lunch: A big salad with lots of dressing or avocado, or zucchini noodles with pesto and grilled salmon.
Dinner: Wild salmon with broccoli, kale or spinach (roasted to make up for any missing fat) or hearty mushroom soup (with veggies, cream and butter/bone broth to satisfy/fill me) or grass-fed beef on a low carb wrap with a ton of roasted veggies.
Dessert: Forget it! I tried to skip after-dinner eating, but sometimes enjoyed a no-added-sugar coconut bar.
Snacks: Nuts, dried cheese, jerky or no-added-sugar coconut chips (if I got hungry at midnight, I had 1 tablespoon of olive oil).

Advertisement

The ‘keto flu’

As my body moved from relying on a steady supply of glucose to ketosis, or fat-burning, the “keto flu” hit. I felt tired, had wild sugar cravings and was mean to my poor husband. It was a rough start.

Then the clouds lifted. Suddenly, I felt great, no longer irritable or “hangry.” A quick urine check revealed I was well on my way to ketosis.

Biggest challenges

I thought it would be hardest to consume enough fat and so few carbs. But protein was my greatest challenge. (No wonder coconut oil, egg yolks and bacon are so popular in keto recipes — they’re high in fat but moderate in protein).

Also, as my body transitioned away from a whole-grain and bean-based fiber diet, I developed a bad bout of constipation and had to up my intake of non-starchy vegetables.

It was also hard to stick with the ketogenic diet while traveling, so planning ahead is a must.

Biggest benefits

Even on tough days, I knew I could give up all sugar and be fine. This felt amazing and empowering. It was one of my top takeaways.

The other surprise was my complete lack of hunger. I knew that fat filled you up. But once the initial shock subsided, my hunger subsided, too.

My calorie consumption was at an all-time high. That’s because, gram for gram, fat calories are more than double the calories of carbohydrate or protein. Yet I lost weight, my clothes fit better, and my belly deflated.

A word of caution

While the short-term effects of the keto diet seem positive for weight loss, some experts advise caution. In fact, this diet ranks No. 39 out of 40 diets reviewed by U.S. News & World Report.

Why? Because medical experts say little is known about the diet’s long-term effects. We don’t know what happens when you eat so much fat and so few carbs over time.

Experts also warn people with liver and kidney conditions to avoid the ketogenic diet. So it’s wise to check with your doctor first.

If you get the green light

If your doctor thinks you’ll be OK on the diet, start planning meals that meet the fat, carb and protein guidelines above. Using an app to track snacks and meals can help, as can investing in some ketogenic cookbooks.

I personally haven’t opted to follow the ketogenic diet. But I have taken a few things from it. I’m now eating:

  • Fewer carbs (without so many restrictions on the type of carb).
  • More protein (mainly baked chicken, on occasion).
  • More fat (focusing on heart-healthy monounsaturated and polyunsaturated sources).

If you get the go-ahead, chances are you’ll be able to lose some weight on the ketogenic diet. Just be patient during that first week. And check in with your doctor periodically to make sure all is well.

Advertisement

By: Kristin Kirkpatrick, MS, RD, LD

Advertisement

Cleveland Clinic icon
Health Essentials logo
Subscription icon

Better health starts here

Sign up for our Health Essentials emails for expert guidance on nutrition, fitness, sleep, skin care and more.

Learn more about our editorial process.

Related Articles

close up of keto gummies
August 24, 2023/Weight Loss

Do Keto Gummies Work for Weight Loss? Are They Safe?

Research is inconclusive whether or not these supplements are helpful

Eggs, avocado, bacon and cheese on a plate.
September 26, 2022/Nutrition

What Is the Keto Diet and Should You Try It?

The high-fat diet can be beneficial for those who have obesity or diabetes

Keto diet and your heart
December 30, 2021/Heart Health

Is the Keto Diet Heart-Healthy?

Find out how this low-carb diet affects your heart

A stack of seed-based crackers
April 29, 2019/Nutrition

Keto-Friendly Snack Ideas to Hold You Over Until Dinner

Reach for quality whole foods first

woman slicing healthy bread with nuts
April 10, 2019/Nutrition

How to Smoothly Transition Off the Keto Diet

3 tips for quitting keto and avoiding weight gain

Person slicing raw chicken on cutting board, with oil and spices
February 16, 2026/Diabetes & Endocrinology

Is a Ketogenic Diet Good for Type 2 Diabetes?

Keto can reduce blood sugar, but that doesn’t mean it’s right for everyone

Person with salty, sweet and fatty snacks, with french fries, chocolates and soda pop
February 9, 2026/Women's Health

Understanding Your Period Cravings

Cravings are a natural response to hormonal changes, but giving into them may make you feel worse

Caregiver and child preparing a salad together
February 5, 2026/Genomic Medicine

Foods To Eat and Avoid on a Phenylketonuria (PKU) Diet

People with PKU need to avoid high-protein foods, like meat, dairy, legumes and whole grains

Trending Topics

Child playing soccer, being hit in head with soccer ball

The 6 Stages of Concussion Recovery

Getting back to normal after a head injury takes time — and patience

Caregiver helping happy child put on snow pants

Here’s How To Prevent Cold Stress

Dressing in multiple layers, drinking warm liquids and taking breaks indoors can help prevent these cold-weather injuries

Red, yellow and green bell peppers in baskets at market

Health Benefits of Bell Peppers

Pick bell peppers to help fight cancer, memory decline and joint pain

Ad