Carb timing and nutrient timing has been debated frequently during the past 10-20 years.
The subject forms part of the wider topic of nutrient timing, which, in itself, is a fairly simple technique to understand and apply. Basically, it ensures that the food you are eating gets used for its intended purpose (energy and muscle growth) rather than being converted into body fat.
Carbohydrates in particular require nutrient timing to the greatest extent, compared to fats and proteins. This is largely because many people consume far too many carbohydrates, relative to the energy demands of their body.
When this occurs, it leads to excess calorie and carb consumption, leading to unwanted weight, fat gain and insulin resistance.
In this article I’ll give you a brief overview of how carbs are digested, why nutrient and carb timing is important, followed by some research proven strategies to time them correctly for optimal effect!
The Fate Of Carbohydrates – Metabolism 101
Before understanding how to use nutrient timing to your advantage, you first need to briefly understand how various macronutrients get used and why timing the ingestion of them relative to your workouts makes a big difference.
Carbohydrates are chains of sugar molecules of varying length. Short chain carbohydrates, such as glucose, are called simple carbohydrates. This means that when consumed, they either need minimal or no breakdown at all to be transported into the bloodstream.
Complex carbs on the other hand have much longer chains and do need to be broken down. This takes time and slows down digestion.
While some people overemphasize this, ultimately, once carbohydrates are ingested and broken down, they all end up as the simplest sugar possible anyway (known as glucose).
From here, glucose enters the bloodstream and has a number of different fates, briefly summarized below.
1. Glucose Gets Used For Immediate Energy
If energy demand is very high, such as during a race or workout, glucose can be used immediately to create a usable form of energy by the body called ATP. In this case, glucose would be required and the risk of gaining body fat as a result is almost zero.
2. Glucose Gets Stored In Muscle As Glycogen
The second fate of glucose is that it gets stored in the muscle as glycogen.
This is largely dependent on activity levels and restriction of carbs. If food is scarce or activity is high, the stored glycogen in the muscle gets converted back to glucose to be used for energy, such as in step number 1.
Eventually, the storage of glycogen becomes depleted. In this case, any carbohydrate that is ingested will likely be transported to the muscle and stored as glycogen in a daily cycle.
Again, in normal conditions or for athletes, when activity is high and glycogen is low, the chance of fat gain is minimal.
However, for a lot of regular people, their activity is likely low so they don’t burn the carbs straight off as glucose and they consume too many carbs, meaning their glycogen stores are always full.
This leads to problems and fat storage, as discussed in the next point.
3. Glucose Gets Stored In Fat Tissue Via A Process Called De Novo Lipogenesis
De Novo Lipogenesis is the process by which the body transforms non-fat energy sources into lipid. For instance, when carbohydrates are turned into body fat (1).
Fortunately, this process is actually quite difficult and last on the list of fates in a normal healthy diet when you exercise on a daily basis and eat a moderate amount of carbs.
However, for some people De Novo Lipogenesis can occur daily, as they simply consume too many carbs, calories and don’t exercise enough. If this situation occurs, the risk of accumulating body fat as a result of carb consumption is high.
As you can see, carbs are not bad, they are just a tool that must be tailored to you and your needs. Ultimately what is bad is too many calories, too many carbs and no exercise. Just like dietary fat, if you combine high calorie intake with low calorie output (exercise) fat gain will occur!
Nutrient Timing To Make Carbs Your Friend!
As you can maybe start to see above, the 3 scenarios described are all dependent on timing as well as quantity.
In essence, you can use your activity level and the extent of activity to determine when you consume carbohydrates and the amount. By doing so, you can deliver them to the body when needed and when you know they’ll be used for fuel, rather than risking excess fat storage.
Carb Back Loading And Cycling
One primary way to use carb timing to your advantage is to hold off on eating your carbohydrates until after your exercise sessions and cycle your carbs based on activity.
In fact, this is one main unique part of my famous 90 Day Bikini plan, which uses advanced carb cycling rotations tailored to the workout days, helping lots of people eat more carbs while shredding body fat.
There are two distinct reasons for considering this technique and below I provide an overview.
1. You Can Base Your Carb Consumption On Your Activity
Carb cycling is a fairly new technique where you base your daily carb consumption on your level of activity.
If you’ve had a light or restful day, you can consume fewer carbohydrates as they are likely not required (remember, they fuel high intensity exercise, not a Sunday all day Netflix binge!).
With a low volume of exercise, the chance of depleting muscle glycogen is low. Remember, in this case, if you consume higher amounts of carbohydrates and they can’t be burned in stage 1 or 2, there is a greater risk of storing them as body fat.
In essence, on light, low volume or rest days, consume a small amount of carbohydrates as opposed to consuming large amounts on heavy, high volume days.
Using this method ensures you’re only consuming the carbs you need and when you break it down like this, it’s just logical and makes perfect commonsense!
2. You Consume Carbs When The Muscle Is Most Receptive
Interestingly, exercise plays a role in how willing the muscle is to receive glucose or the carbohydrates you eat.
When muscle contraction occurs, a transporter in muscle cells called GLUT 4 is transported to the surface (membrane) of the cell. In this case, it makes transporting glucose into the muscle a simple task (2, 3, 4).
However, this really only occurs with exercise – hence the idea of timing your carbs around the workout. By waiting to consume carbs until this GLUT 4 transporter is available during and after you train, you make it more likely that consumed carbs will be shuttled to muscle tissue, rather than body fat.
To simplify that, the GLUT 4 acts as a gatekeeper. When you exercise, it runs to the gate and opens it fully, letting all the carbs or glucose easily move inside to be stored as glycogen and not fat.
Choosing The Right Carbohydrate Source
As mentioned briefly, carbs tend to either be simple or complex. The greater the complexity, the longer it takes to digest.
The speed at which carbs are ingested plays a role in both how hungry you are and how insulin responds to some degree.
When complex carbs are consumed, it’s more difficult for the body to digest them compared to simple carbohydrates such as sugar. They consist of grains or potatoes, which also tend to have more fiber, further slowing digestion. In doing so, this slows the speed at which food exits the stomach, providing an appetite suppressant effect.
Secondly, without going into too much detail, when carbs are consumed they elicit an insulin response to remove sugar from the blood. However the speed (based on the type) and amount of carbs entering the bloodstream elicits a different response (5, 6).
For instance, a large amount of sugar elicits a faster and greater insulin response than would, say, a bowl of raw oatmeal.
Technically, a large and fast insulin spike isn’t inherently bad in the short term. But (and it’s a significant but) if it occurs chronically, it can present issues leading to disease states and obesity (7).
For this reason, and in addition to appropriately timing your carb intake based on exercise, you should also adjust the type of carbs you are consuming according to exercise as well.
To simplify it, here’s a breakdown:
Pre/During/Post Workout: Around the workout easily digestible carbs are more suitable as they can easily be metabolized and are easier to digest, providing quick energy. This isn’t to say you can’t consume complex carbs as well, just ensure they are easily digested and don’t cause bloating or stomach discomfort. Aim for around 25-50g carbs 1-2 hours pre-workout (if your goal is fat loss you can consume protein only) and then a similar amount around 1-2 hours post workout.
Away From The Workout / Rest Days: Slower, more complex carbs are best in general, mainly because they tend to be from healthier sources, such as grains and vegetables, which have added fiber, more water and a lower calorie density. Of course, if you are on a lower carb diet you may eat protein and fats all day, saving your daily carb intake to pre/post workout when you will maximize their benefits – something i highly recommended to those trying to lose fat.
In essence, when energy demand is high, having simple, fast digesting carbs is more acceptable, whereas during times of low activity or energy demand, opt for slower digesting, complex carbohydrates. For example, some sugar cereal isn’t a great choice for breakfast when you are sat in an office all day. But, if you really want to eat that daily, taking it pre-workout could actually enhance performance – as you can see, timing is key!
Finally, do not feel too overwhelmed about the type of carbs, as this is a little more advanced and so, if you are still working on the fundamentals, the TOTAL amount of carbs, calories and other nutrients is far more important to focus on.
Nutrient Timing Tips To Make Carbs Work For You, Not Against You
Nutrient timing is a technique to ensure that the food you are eating gets used for its intended purpose.
This technique works especially well for carbohydrates since you can adjust when, how much and which type of carbohydrate you consume, based on your activity level and energy demands.
In short, you want more carbs around the workout and on workout days. The more intense or the longer the workout, you generally want more carbs to support it.
While it may sound confusing initially, it ultimately boils down to this key principle. Of course, once the basics are in place you can take things a stage further, as we do in our 90 Day Carb Cycling Meal Plans.
If you want to get all this ready done for you so that you can then just follow a simple meal plan where you know exactly what to eat and can feel confident in the knowledge that you have carbs working for YOU and not against you, download my meal plans here and save 85% off the RRP.
- Acheson, K. J., Schutz, Y., Bessard, T., Anantharaman, K. R. I. S. H. N. A., Flatt, J. P., & Jequier, E. (1988). Glycogen storage capacity and de novo lipogenesis during massive carbohydrate overfeeding in man. The American journal of clinical nutrition, 48(2), 240-247.
- Mitsumoto, Y., Burdett, E., Grant, A., & Klip, A. (1991). Differential expression of the GLUT1 and GLUT4 glucose transporters during differentiation of L6 muscle cells. Biochemical and biophysical research communications, 175(2), 652-659.
- Gollnick, P. D., Piehl, K., & Saltin, B. (1974). Selective glycogen depletion pattern in human muscle fibres after exercise of varying intensity and at varying pedalling rates. The Journal of physiology, 241(1), 45-57.
- VØLLESTAD, N. K., & BLOM, P. C. S. (1985). Effect of varying exercise intensity on glycogen depletion in human muscle fibres. Acta Physiologica, 125(3), 395-405.
- Aller, E. E., Abete, I., Astrup, A., Martinez, J. A., & Baak, M. A. V. (2011). Starches, sugars and obesity. Nutrients, 3(3), 341-369.
- Daly, M. (2003). Sugars, insulin sensitivity, and the postprandial state. The American journal of clinical nutrition, 78(4), 865S-872S.
- Bessesen, D. H. (2001). The role of carbohydrates in insulin resistance. The Journal of nutrition, 131(10), 2782S-2786S.