Post Workout Nutrition

By Paleo
In Paleo Tips
Jan 14th, 2013


Just how important it is to fuel yourself after a workout? In my opinion, it depends… it depends on your goals and it also depends highly on how good your nutrition throughout the rest of the day is.

Post workout nutrition (PWO) is a much debated topic, some people will swear by the importance of PWO nutrition within 30-40min of finishing a workout, while others will claim it’s not as important as made out to be. In this article I will cover both topics and explain the reasoning behind them.

A post-workout meal could be a solid meal or liquid nutrition (meal replacement shake). When it comes to PWO nutrition soon after exercise, liquid nutrition is known to be an easy way to get the nutrients to the muscles quickly while they are highly receptive to it. The theory is that the insulin elevation brought on by a PWO shake will help shuttle carbohydrates and amino acids (proteins) into muscle cells and encourage protein synthesis.

If you’re goal is to increase muscle mass, I would recommend a post workout shake within a maximum of 40min of finishing up your exercise session, and following up with a meal 60-90min later. The post workout shake should consist of high GI (Glycemic Index) carbohydrates, protein, micronutrients (vitamins, minerals, antioxidants, enzymes, etc) and should be low in fat.

In this case, it’s necessary to consume enough carbohydrates to promote a substantial insulin release, as spiking the insulin hormone will open up the window for carbohydrates and proteins to get into the muscles and start repairing tissue. It’s hard to say exactly how much carbohydrates you should consume, because if you consume too much the excess carbohydrates not used could turn into stored body fat.

Research has shown however, that an intake of 0.8 to 1.2 grams per 1kg of body weight (that’s lean body mass), increases the insulin response and accelerates protein/muscle repair. If you want to use this math, I would recommend 0.8g of carbohydrates per 1kg of lean body weight, unless you have done a really long intense training session, in which case you may feel better consuming more.

It’s also important to include micronutrients in your initial post-workout nutrition, as the micronutrients help in the transportation of protein to muscles, and dramatically enhances the rate of repair of muscle tissue (as there are more nutrients the body needs and can use). In addition, during a workout session, the body’s immune system gets damaged and increasing the micronutrient consumption post-workout and during the rest of the day, will help boost the immune system back to optimal/above optimal levels.

Make sure though that your workout is worth it. A 30min high intensity session probably won’t bring your glycogen levels down low enough for them to need to be replaced. If you have a high GI post workout drink and your glycogen levels aren’t lowered, chances are you’re probably just going to spike your insulin levels higher than they need to be to contribute to long term health benefits, and as a result you will store fat.

Now, if your goal is to reduce body fat then there is a whole other side to the PWO nutrition story, and that is to not have PWO nutrition directly after a workout session, but to fast (not eat) for 1.5-2hrs after your session.

The main factor to keep in mind here is what nutrition you are eating during the day, if you are providing your body with efficient amounts of protein, carbohydrates, fats and micronutrients during the day, a post-workout nutrition shake/meal isn’t all that necessary especially if the body composition goal in mind it to reduce stored body fat.

I will only recommend fasting after a workout if you have an extremely good diet throughout the day (meaning you are providing your body with efficient amounts of protein, carbohydrates, fats and micronutrients), as this nutrition alone should be enough for the body to repair itself after a workout, leaving a post-workout nutrition shake/meal becoming not all that necessary, especially if the body composition goal in mind it to reduce stored body fat.

If the day’s nutrition is solid, I see no reason why muscle repair and performance goals would be affected by a lack of initial post-workout nutrition. If you do not eat a good diet however, then you just won’t be fueling your body correctly for this to take place.

The idea of a post workout fast isn’t to starve yourself in order to reduce your total calorie intake, the idea however is too delay the meal in order too obtain the benefits of fasting without the calorie deficit. Calorie depriving is a whole different topic all together, but in short, calorie depriving is not good for you in the long term.

A 1.5-2hr fasting window after a workout will require the body to burn up energy; if there is no energy coming in through food consumption, the body will look elsewhere, and the number one place for that is stored body fat. Hence the reason the post-workout fast can be quite beneficial to those wanting to reduce body fat.

So make sure your diet is good, which it should be anyway if you are wanting to achieve optimal health and performance. Un-fortunately I know too many people who believe they eat really well, but in reality have a very poor diet in regards to nutritional quality and quantity. So here are some quick pointers on determining whether or not your diet will balance up a post workout fast;

If you don’t feed your body bad foods (i.e. grains, starches, sugar, processed foods) instead of real food, you are most likely eating healthy and your body is running effectively. On a more thorough note though, when it comes to looking into your diet on a daily basis, if you eat the following, you are definitely on your way to good heath;

  • Eat at least 1.2g protein per Kg of lean muscle mass
  • Obtain carbohydrate sources from fruits and vegetables
  • Consume omega3 fish oil everyday
  • Consume enough calories for your body to function properly
  • Be consistent with good nutrition

If you are un-sure about the quality of your meals and your nutrition, monitor it for a week and look over it, measure and write down the food you eat, you may be surprised at what you are actually eating.

In conclusion, if you want to lean out, delaying your PWO nutrition could be a good option. But if you want to put on muscle mass or have just completed a long workout where your glycogen levels are low, a PWO nutrition shake may become pretty important.

And if you’re still un-certain as to what to do, play around with what happens to your body composition when having a PWO shake Vs not having one, then make a decision. There are many studies out there which will show benefits in both of these situations, but its best if you take a personal approach on the situation and see what works best for you, as there isn’t a single protocol that works well for everyone.

11 Responses to “Post Workout Nutrition”

  1. zina saheb says:

    thank you for that info!
    What PWO do you recommend? What type of carb/protein shake? there are vassel and non..i am not sure which is the best.. I am 35 train crossfit 5 days a week and is loosing fat same time as building muscle, so i guess i want to keep my muscles not loose them;)


  2. Lisa says:

    Answers all of my questions! Thank you!

  3. Michael barousse says:

    Great Article! Thanks!

  4. Ashley Saliba says:

    Wonderful! Answers SO many questions that I couldn’t elsewhere!

  5. jenny says:

    Fantastic article!!

  6. PaleoDoc says:

    I have been working with PWO nutrition for many years with my patients and I find that it is an essential component whether you are looking to gain lean, lose fat or both. I conclude this based on physiologic and clinical parameters. After a workout there is depletion of muscle glycogen and muscle protein damage. This can occur even with a 15 minute intense workout – crossfit routines are perfect examples and I work with many crossfitters. In the 30-40 minute period following a workout the goal is to get simple sugars and protein into the muscle cells or these cells will begin to cannibalize their own protein in order to replace the lost glycogen, leading to muscle loss. Even without insulin there is a passive movement of protein into cells in the post workout setting but simple sugars are more dependent on the insulin. The BCAA content of whey protein will kick up the insulin secretion by the pancreas by about 220% in response to the glucose. All of this is beneficial in getting the muscle fed and repaired. This has also been shown to substantially increase the metabolic burn time after a workout. Lack of a PWO shake has routinely led to muscle loss in my patients which we determine by DEXA scans. So you will lose weight but it will be a combination of fat and muscle. Sarcopenia is unhealthy and nearly as common as excess fat so I highly recommend using a PWO shake with adequate protein (whey isolate), BCAA, and carbs. Typically we use 60-75 grams of carbs for lean increase and 25-45 grams for lean maintenance.

    • Matt says:

      Hi PaleoDoc

      I agree to a point.

      However, I’ve always wondered… What about the blunting effect that insulin has on natural GH release? After intense exercise, wouldn’t BCCA’s and Glutamine be much more beneficial as they will produce a much lower, if any, insulin reponse?

      Obviously more considering someone whose ultimate goal is to lose as much fat as possible whilst preserving lean muscle.

      Very interested to hear your response.


  7. Katherine Piao says:

    Hi I’m 16 and I just wanted to know if there is a danger in becoming fat when using a weight gainer protein ??

  8. mike chang says:

    What days do u propose POW on crossFit?

    Rest times? Or right after lifting days?

  9. miriam says:

    Write more, that’s all I have to say.

  10. felix says:

    what’s your thought on the naked protein juice?

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