January 22, 2018

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.


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).

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.

By: Kristin Kirkpatrick, MS, RD, LD

Related Articles

Fish, vegetables and other whole foods on a table.
February 15, 2023
What To Eat (and Avoid) When Living With IgA Nephropathy or C3G

Low-sodium and nutrient-rich foods are your best bets

Table of food groups within the paleo diet.
February 3, 2023
Paleo Diet 101: What You Can and Can’t Eat

You’ll eat plenty of fruits, veggies and lean meat, but you’ll have to eliminate grains and dairy

Healthy diet of fruits and vegetables
October 19, 2022
Anti-Cancer Diet: These Foods May Reduce Your Risk for Cancer

7 healthy eating tips to help reduce your risk of some of the most common types of cancer

Farmer's market aisle.
October 14, 2022
12 Inexpensive Healthy Food Choices

Here’s what to add to your grocery list and how you can pull together cheap but healthy dinners

plant paradox farmers market vegetables
May 31, 2022
Plant Paradox Diet: Does It Work for Weight Loss?

The much-hyped eating program focuses on eliminating lectins from your meals

Recipe: Zucchini Raisin Muffins
October 12, 2021
Healthy Muffin Recipes: Pumpkin, Apple, Chocolate and More — All Under 200 Calories

Easy and delicious for breakfast, snack time or anytime!

healthy snacks at work
February 12, 2021
5 Tips To Help You Snack Healthier at Work

What you eat between meals matters

chia seeds
January 13, 2021
The 6 Best Seeds to Eat

How to incorporate seeds into a healthy diet

Trending Topics

group of hands holding different beverages
November 14, 2023
10 Myths About Drinking Alcohol You Should Stop Repeating

Coffee won’t cure a hangover and you definitely shouldn’t mix your cocktail with an energy drink

Person applies moisturizer as part of their skin care routine after a shower.
November 10, 2023
Korean Skin Care Routines: What You Need To Know

Focus on the philosophy — replenishing and respecting your skin — not necessarily the steps

glass of cherry juice with cherries on table
November 8, 2023
Sleepy Girl Mocktail: What’s in It and Does It Really Make You Sleep Better?

This social media sleep hack with tart cherry juice and magnesium could be worth a try