Cardio Empty Stomach Vs Post-Workout for Maximum Fat loss

Everyone loves to lift but hate doing cardio. After all its “Cardio is the nemesis of muscle building” or is it? Cardio should be a big part of everyone’s workout. If its not part of yours, then we recommend you add it. Unless you are on the plan called “FOREVER BULK”, you will find this post interesting.

At GYMINUTES, not only we strive to achieve best possible workout to gain muscle, we try to evaluate each and every aspect of working out. One of the questions we are trying to answer in our lab is, “Is working out in morning is better than working out in the evening?”

Even though it may seem like a simple question, it is pretty complex to answer. Why?

When we say working out in the morning, do we mean working out empty stomach or post breakfast. Similarly, if you workout in the evening, how long after you had your pre-workout meal. 1 hour, 2 hour or 3 hours before you start your workout? We are still trying to analyze and verify our findings w.r.t lifting weights. But what about cardio? Cardio is a crucial part of bodybuilding, powerlifting and strength training.

At GYMINUTES, we are trying to answer similar question as above about doing cardio. Is cardio empty  stomach better than doing it post-workout?

If you are interested in reading research paper of this and a detailed article, please click here. If you are just interested in summary, read below.

Summary of article:

The article above basically consist of data from different studies performed by scientist on affect of cardio on empty stomach, post breakfast, 50 mins in morning and 50 minutes in evening. The cardio exercise used was stationary cycling. The parameters used to measure the affect were VO2(oxygen consumption) and RER (substrate utilization, estimated by the respiratory exchange ratio).

The assumption as mentioned in the article is

“The basic premise for this practice is that low levels of glycogen (and/or glycogen depletion during the exercise bout itself) and insulin, shift energy utilization away from carbohydrate for fuel, thereby allowing greater mobilization of stored fat that can be used for fuel (fat oxidation). “

After various tests it was found that in short term, you may burn 50 more calories (330 kcal in morning vs 280 kcal in evening) over 24 hour period by doing cardio empty stomach vs doing it in the evening. But this is primarily contributed to transient energy deficit in the morning.


If above conclusion is true, then doing cardio in morning does not have much advantage than when done in evening. If at the end of the day, you are burning 50 more calories, then you can adjust your diet to consume 50 less calories or  workout for 5 more minutes in the evening post workout. However, here are possible reasons why you would want to do cardio in morning or evening


  1. You are a morning person.
  2. You like to lift in evening and don’t want to spend 2 hours in the gym.


  1. You like to go to gym 1 time and you are done.
  2. You are not a morning person.

So to finally  answer the question if cardio is better done in morning vs in the evening, our take is


But if you are like us, who wants to optimize the cardio session then this study can provide basic steps on identifying best cardio time for an individual to maximize the calories burned. So thats what are going to do next.

Further investigation and Our testing.

We are now curious on repeating this test on ourselves and see if we can identify our our best cardio time. Specifically the whole “transient energy” thing. Over period of next 1 month, we will be doing following tests

Perform Cardio 4 times per each week at speed of 2.5 mph for 45 minutes on 10 incline level of treadmill.

Week 1 – 2: 45 Minutes Cardio pre-breakfast (empty stomach)

Week 3 – 4: 45 Minutes Cardio immediately after workout.

(Note: We are using treadmill because 1) we only have treadmill 2) 45 min treadmill on incline 10 with 2.5 mph burns same calories as 45 stationary bike)

What we plan to measure?

As we don’t have fancy equipments yet to measure VO2 and RER, we will be using run-of-the-mill workout tracking bands. In addition to that, we will measure

  1. Energy level (0 – no energy, 10 – 3 scoops of pre-workout) before every cardio session
  2. Calories burned – during cardio session
  3. Weight change – daily
  4. Body fat percentage change – daily

As we are measuring weight and BF, we will limit calories to 2300 kCal per day.

What we are really looking for on Cardio Empty stomach vs post-workout?

As per the study above, the major difference in calories burned was caused due to transient energy level.

So what it implies that the lower transient energy you have, the more calories you will burn, thus more weight and body-fat you lose. As energy level is different for each person, we will try to identify what is our lowest energy level time and then do cardio that time everyday. As we don’t have an account on the amount of energy we have in morning and post-workout, this experiment will help us find that out. After 4 weeks, which ever test period of 2 weeks had higher weight loss and body-fat loss by percentage, will be indicative of our ideal cardio time.

We will publish our results weekly starting on June 6th 2016.

If you want to join us on our journey, start your own test and leave a comment below. If you have any questions, send us an email at “”

Also if you are looking to track your workouts and analyze your progress, download “GYMINUTES” for FREE from IOS app store. We promise, it will be the best workout tracking app you will ever use.