Published on Apr 14, 2019. 9 minute read.

Exercise can have a profound impact on your body and the amount that you participate in each week can have a dramatic impact your emotional, mental and physical health. People who are overweight, or obese, consuming the standard western diet can have difficulty accessing stored energy (fat) and can find the experience tiring, stressful, emotionally draining, and unrewarding. Eating keto will result in lower blood sugar levels and decreased insulin resistance, resulting in better utilization of energy. This chemical and hormonal change in the body often leads to an increase in people’s desire to exercise.

So, should you exercise when starting the ketogenic diet? Almost certainly not.

Tiredness is a big problem when starting keto
Tiredness is a big problem when starting keto
Tiredness is a big problem when starting keto

Keto flu

The keto flu is not the flu in the traditional sense. The keto flu is not a respiratory illness caused by the influenza virus. The keto flu is called that because people who start keto often experience flu-like symptoms. This includes;

  • Tiredness
  • Headaches
  • Dizziness
  • Nausea
  • Broken sleep and irritability
  • Muscle cramps

Typically the keto flu lasts anywhere from 1-4 weeks. Attempting to exercise during the transition, whilst possible, will be more difficult than before. The body will have less water and salts available for sweating and proper muscle function.

Headaches, dizziness and nausea are common when exercising during the transition period, and may make you feel unwell.

Most of these symptoms can be managed. Your could take off-the-shelve or over-the-counter medication to control these symptoms, or simply take some time off if you are already going to the gym on a regular basis.

Exercise during the first 2 weeks

If you are currently exercising and/or going to the gym on a regular or semi-regular basis, you might want to consider taking some time off. If you are insistent on sticking with your routine through thick and thin, then you should consider having a deloading week or training with a friend to ensure your safety and prevent avoidable injury.

If you are currently inactive, or get less than 30 minutes of light to moderate exercise a day, then you have two options;

  1. Stay inactive during this phase. As your energy levels may be lower during the first few weeks, you might want to consider avoiding exercise altogether. Ride it out and wait for your energy levels to return once you are producing ketones and become keto adapted.
  2. Take brisk walks daily. You can accelerate your transition to ketosis by taking brisk walks for between 30-60 minutes per day. This will speed up your transition because your body will use glycogen (concentrated form of sugar) stored in the muscles for energy and will have to produce more to replenish those depleted stores. Your body will start a process called gluconeogenesis (in the liver) to produce more from various amino acids and protein.

Consider going for brisk walks several times a week for 30-60 minutes if you feel comfortable and happy to do so.

Monday, Wednesday, Saturday, SundayBrisk 30-60 minute walk

Exercise after the transition period

When you become keto adapted, your body will switch to using ketones for energy. Ketones are a fantastic source of energy and people usually find that they feel more energetic than before.

The big secret of weight loss (hint: it is NOT killing yourself in the gym every day)

We do not consider running on a treadmill a few times a week to be the best use of our time. If you go to the gym and run on a treadmill for 1 hour, 3 times a week and change nothing else in your life, chances are you will either stay the same weight or even gain weight. You may gain weight because your body will store more water for muscle function. Weight loss will only come when coupled with balanced and complete nutrition. As you are now following keto, you are halfway there. However, the age old principle of Calories in vs Calories out still applies. If you consume more calories than your body requires, you will continue to gain weight.

The secret to effective weight loss is to eat a calorie deficit. The secret to effective weight loss is to eat less calories than your body requires. Exercise can be an effective tool to accelerate weight loss.

Understanding your body’s caloric requirements

There are various calculators and websites dedicated to helping you calculate how much nutrition your body needs to function and thrive.

TDEE. Total Daily Energy Expenditure.

TDEE is a formula used to determine how many calories your body needs on a day to day basis, taking into consideration your; age, height, weight, and level of physical activity.

TDEE takes your base metabolic rate (BMR, the number of calories required to live, assuming you were to do nothing but rest for 24 hours), your level of physical activity, and the thermic effect of food (the caloric cost of processing food) to calculate the number of calories you require, as a rough estimation.

If you plan to lose weight in a slow and controlled manner, you would want to take your TDEE and subtract between 250-500 calories a day to result in 0.5-1lbs of weight loss per week.

Have a look at for calculate your personal TDEE.

Let’s say your TDEE is around 2000 calories a day. Should you consume 2500 calories a day, you would gain 1lbs of weight over the course of 1 week. Were your calorie intake 1500 per week, you would lose 1lbs of weight a week.

This is an oversimplification because there are other factors that contribute to weight loss, such as water retention and muscle mass, but is a useful guideline.

Set fitness goals

Before starting any sort of fitness program, you should understand what you are trying to achieve. Too many people go to the gym week in, week out, with no clear goals in mind. Going to the gym becomes robotic and unfocused for them, and they experience little to no results and may eventually give up.

Each goal you set should consist of 3 parts;

  • A time frame: by when should this goal be achieved?
  • The end goal: what should you achieve?
  • The process: what do I need to do to reach this goal?

Your fitness goals should look something like this;

  • In one month, I will lose 8 lbs by eating a 500 calorie deficit per day and increasing my TDEE by exercising 3 times a week for 60 minutes.
  • In 4 weeks, I will be able to climb the 4 flights of stairs to the office without stopping, by practising every day.
  • In 3 months, I will reduce the amount of medication I take daily, by sticking with keto and visiting the doctor regularly to track insulin requirements.

Each goal clearly defines how long it should take to achieve each objective (timeframe), what the result is (outcome) and what the process is (how to achieve the outcome within the timeframe).

When you have set yourself ambitious, but achievable goals, you should forget about the end result and trust the process.

We recommend that you do not measure the result too often. For example, if your goal is to lose 2lbs of weight in a week, do not weigh yourself every day. As long as you are sticking with the process each day, the results will come. Weighing yourself once or twice a week would be sufficient in this case. Trust the process and the results will follow.

Weight training can radically accelerate weight loss

Beginner weight lifting routine

If you are an absolute beginner, you will likely see rapid results in the early days, regardless of what training program you undertake. If you have neglected training for several years, any exercise you start doing will immediately shock the body and muscle gains will come fast. Over time the gains will slow.

We have provided the following routine as a rough guide only, and we recommend that you try each exercise at least once and determine if it is comfortable for you. Exercising should feel good after a while, and if any exercise is causing you any kind of physical pain, you should stop immediately and see professional advice.

Always start by lifting very light, and then gradually increase the weight over time. Lifting too heavy too early will lead to serious injury.

1Treadmill5 minutes
Back squats3 sets, 6 reps
Romanian deadlift3 sets, 10 reps
Calf raises3 sets, 15 reps
2Treadmill5 minutes
Flat bench press3 sets, 10 reps
Declined bench press3 sets, 10 reps
Inclined bench press3 sets, 10 reps
3Treadmill5 minutes
21s - Arm curls3 sets
Arnold press3 sets
Tricep pull downs3 sets, 8 reps

The above programme is designed to get you into the gym about 3 days per week and targets different muscle groups on different days. If at all possible, alternate the days in which you go to the gym. For example, go on; Monday, Wednesday and Friday. Even though you will be targeting different muscle groups in each session, this 24 hour gap is still important because it gives the muscles time to recover, and reduces fatigue.

Tip: Decide on a time that suits you best and go to the gym consistently at that time. If you decide to go to the gym at 6am, 3 days week, then do not deviate from that plan. After a while it will become habit and automatic, making it easier. After a few months of following the routine consistently it will feel strange when you miss a day.

Do not make decisions when you are snoozing in bed in between alarms. The worst time to make a decision about whether or not to go to the gym is when you are lying in bed at 6am and your alarm clock just went off. Chances are you are going to decide to stay in bed and go to the gym “another time”. This will lead to a failure spiral and may result in you never going to the gym ever again!

Make good decisions when the rational side of your brain, not the emotional side, is active… preferably when you are awake, alert and fully conscious. Also, tell people your intentions so they can hold you accountable. Do these things, and your chances of succeeding will dramatically improve.

Exercising/training is not for everybody

Should you decide not to train, or even exercise on a semi-regular or regular basis, then that is fine too. Exercising can be an effective tool for accelerating weight loss, but as long as you introduce calorie deficits, or even better, intermittent/extended/prolonged fasting, weight loss will follow naturally. Listen to your body and make your own decisions to suit your lifestyle.


Exercising can be difficult for people when starting keto, because of the effects of the keto flu. When starting keto, you may consider taking a break from exercising or exercising with a friend for safety and to avoid injury. Exercising can be an effective tool to help accelerate weight loss. You cannot out-train a bad diet, so you may want to determine your body’s caloric needs by using a Total Daily Energy Expenditure (TDEE) calculator. Set yourself some clear fitness goals, and track them closely over time so you can follow your progress. Should you decide that exercising is not right for you, do not worry about it, eating a calorie deficit will result in weight loss (if that is your goal) over time.


Jon Preece

About the author

Jon Preece is a professional front-end development specialist.

For over a decade, Jon has worked for some of the biggest and best UK based companies, on a wide range of products. Get in touch via Twitter.