Exercising in keto


Running or Weightlifting? 3 exercises that help you enter ketosis faster

The most important milestone for ketogenic diet is to let our body adapt to fat utilization and entering ketosis. However, you may get devastated when your body can't produce enough ketones to enter ketosis and cannot get rid of the fat quickly enough. Don't panic, exercise can help. When exercising, we require a substantial amount of energy. To compromise the increase in energy expenditure, our body will increase our metabolic rate. Now, if you have already been following a ketogenic diet and minimizing your carbs intake, fat will be our bodies' major fuel and will be oxidized into ketones for energy production. Thus, more ketone will be produced when doing exercise. In short, exercise is a promising solution for those struggling to get into ketosis and helps you maintain ketosis (and of course burn more fat, lose more weight!!!). But do you know which type of exercise you should do to enter ketosis faster?

Low intensity, steady-state aerobic exercise,like running, swimming, jogging, can help you utilize your fat maximally and turn them into ketones. But why low intensity, steady-state aerobic exercise? Aren't hitting the gym more effective and can burn more fat? The short answer is no. It may come to your surprise that a lower intensity exercise can help you burn more fat than weight lifting and doing push-ups, these kinds of high-intensity resistance training. But it all depends on how much fat you are consuming.

Our body's utilization of substrates in different exercise intensity

With the efforts of our sports scientists, it has now been widely known that low exercise intensity maximizes our fat utilization. The sweet spot of exercise intensity that utilizes your fats as the major source of fuel is in the range of 40%-70% of maximum oxygen consumption (VO₂ max)1,2 or 60%-80% of our maximum heart rate (HR max)3.

Graph 1. Abbreviation: plasma FFA = plasma Free fatty acid. A prestigious study done (2) by Professor Johannes A.Romijn and his colleagues from the University of Texas medical branch studied substrate utilization under different exercise intensity. At 25% VO₂ max, which is our normal non-exercise intensity, the use of fat in our bloodstream (plasma FFA) is the highest. When we exercise and increase our intensity to 65% VO₂ max, there is a slight drop in plasma FFA usage, but at the same time increase the utilization of muscle-stored fat (muscle triglycerides). Therefore, it has the highest fat utilization among the three intensity. At 85% VO₂ max, despite the total energy consumed is the highest, both muscle and blood fat utilization have decreased, whilst muscle glycogen is responsible for most of the energy production at this intensity.

You can see from the graph above, the total energy, but NOT our fat requirements during exercise are increased with higher exercise intensity. When performing low intensity, steady-state aerobic exercises, our body needs an energy source that provides stable energy to support our movement. Fat provides exactly that, a slow but stable and large energy source. More importantly, fat stored in our adipose tissue (our stubborn belly and peripheral fat) will be released to our bloodstream for usage. If we increase our intensity and put more effort, we will start pulling fat in muscle, blood and adipose tissue, which burns the maximum amount of fat.

But once we hit our exercise intensity to above 70% VO₂ max, things change. We need a rapid and immediate energy source to continuously replenish our rapid energy consumed in such high exercise intensity. In light of this, glycogen (the storage form of carbohydrates) and glucose will be the first choice of fuel sources. They can be burnt quickly and provide energy instantly, unlike our stubborn fat. Studies have observed that when we perform high-intensity exercise, less fat is released from our adipose tissue3,4 but the reason behind is not known yet. Furthermore, when our muscle is utilising glycogen, it has also been examined that it will inhibit fat transport into our muscle and limit fat utilization3. All of these lead to burning less fat. 

So if you go to the gym every single day, lifting heavy weights and sprinting very hard, hoping that you can burn more fat and produce more ketones, it is time for you to put down your dumbbells and do some light intensity workout. 

Further information

How to calculate your % VO₂ max and % HR max?

  1. Calculate your maximum heart rate using the formula: 220 – your age = HR max
  2. Take a full 60-second count of your heartbeats using your gadgets (Apple Watch, Fitbit etc.) or taking your pulse with your fingers
  3. Calculate your % HR max by dividing your counted heartbeats against your maximum heart rate
  4. Calculate your % VO₂ max using the formula[3]:

Man : % HR max = 0.636 x % VO₂ max + 38.2

Woman : % HR max = 0.659 x % VO₂ max + 34.6

Or using the Heart Rate and Percent VO₂ max Conversion Calculator: http://www.shapesense.com/fitness-exercise/calculators/heart-rate-and-percent-vo2max-conversion-calculator.com

You may find these numbers sophisticated. But no worries. We will provide you with three exercises that surely can help you burn more fat and produce more ketone.

Three highly suggested exercise


A 30 minutes jog after a nice keto meal every day will be more than enough to help you reach 60% of your maximum heart rate. Let’s go jogging after tonight’s dinner and make it your habit.

Rope jumping

Don't look down on rope jumping. You will find it very exhausting even if you sustain a slow pace (<100 skips/min) rhythmic bounce for 10 minutes. It is a very easy workout for you to do at home, no excuse not to try it.


Swimming is definitely one of the best exercises for every keto person. Not only because it can help you achieve optimal intensity easily, but it also utilizes every major muscle in our body. You can work out your whole body in one go, preventing muscle loss and burn fat at the same time. Swimming in summer is the best!!!

Does aerobic exercise cause muscle loss?

You may have heard rumours from some forums or other keto dieters that aerobic exercise that we have recommended above, will cause muscle mass loss. Frankly speaking, this is correct, but just partly. If we know the science behind it, we will have no problem doing aerobic exercises and retaining muscles at the same time. As we follow a ketogenic diet, our body’s carbohydrates have been drained out and all of our fuel sources come from fat and protein.
Basically, our body will prioritize fat as the major fuel and protein as a very minor fuel since proteins are essential in building up our body & muscles and maintaining many basic functions in our life.

But when you have run out of fats, protein will be the only option to generate energy in the absence of both fats and carbohydrates. Therefore, our muscle protein is the first to sacrifice. So to speak, if we have enough fat intake to support our energy requirement, doing aerobic exercise is not a big deal.

Research has studied some elite gymnasts’ muscle mass change after following a ketogenic diet for 1 month. It has found out that they haven’t lost muscle at all even though they are following aerobic training for a long time6,7. So long story short, remember to consume enough fat and also consume an adequate amount of high-quality protein to maintain a strong muscle. 

Strike your balance

Although low-intensity aerobic exercise is more favourable for you to enter ketosis, still, it doesn’t mean that you should totally avoid all high-intensity exercise. We should all seek a balance between the two. This differs from individual to individual. If you want to test which works for you and which don’t, you will need a Keto breathalyzer to help you monitor everything for yourself. You will know your optimal aerobic and anaerobic workout ratio to enter ketosis and guide you over your keto journey.

Disclaimer: This guide is for general information and references only, it does not constitute medical advice. Individual should have different needs and should closely discuss with your healthcare team.

#3Exercise #enterketosisfaster #Jogging #RopeJumping #Swimming #vegan

1. Kang, J., Hoffman, J. R., Ratamess, N. A., Faigenbaum, A. D., Falvo, M., & Wendell, M. (2007). Effect of exercise intensity on fat utilization in males and females. Research in sports medicine, 15(3), 175-188.
2. Romijn, J. A., Coyle, E. F., Sidossis, L. S., Gastaldelli, A., Horowitz, J. F., Endert, E., & Wolfe, R. R. (1993). Regulation of endogenous fat and carbohydrate metabolism in relation to exercise intensity and duration. American Journal of Physiology-Endocrinology And Metabolism, 265(3), E380-E391.
3. Swain, D. P., Abernathy, K. S., Smith, C. S., Lee, S. J., & Bunn, S. A. (1994). Target heart rates for the development of cardiorespiratory fitness. Medicine and science in sports and exercise, 26(1), 112-116.
4. Horowitz, Jeffrey F. (2003). Fatty acid mobilization from adipose tissue during exercise. Trends in Endocrinology and Metabolism, 14(8), 386-392.
5. Wolfe, R. R. (1998). Fat metabolism in exercise. Skeletal Muscle Metabolism in Exercise and Diabetes, 147-156.
6. Ma, S., & Suzuki, K. (2019). Keto-adaptation and endurance exercise capacity, fatigue recovery, and exercise-induced muscle and organ damage prevention: a narrative review. Sports, 7(2), 40.
7. Paoli, A., Grimaldi, K., D'Agostino, D., Cenci, L., Moro, T., Bianco, A., & Palma, A. (2012). Ketogenic diet does not affect strength performance in elite artistic gymnasts. Journal of the International Society of Sports Nutrition, 9(1), 1-9.


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