We sent out an email a while ago on protein serving sizes, mentioning the role of protein distribution across the day for muscle building. In response to that email, Caroline asked an excellent question:
What about fasting? I would workout at 7am 4 mornings a week.
I could fast anything from 16-20 hours my first meal being at the earliest 1pm, it normally consists of a meatzza and some carbs and veg, so approx. 60g protein.
Are there any negative effects by doing this? Am I reducing my body’s ability in building muscle or does it matter, as long as I hit my 120g worth of protein in that eating period.
This is a great question, and it's one that we often get asked by our clients. We place a big emphasis on viewing the optimal approach as one that is practical. As I am sure you know, dietary adherence can be very difficult. Sticking to a specific protocol is not easy, nor is following even a handful of nutritional guidelines. Therefore, we like to focus on what suits the individual, which, in this case, seems to be
an intermittent fasting type of approach.
So, there are a couple of components to Caroline's approach:
- 16-20 hours of fasting.
- Training in the morning.
- First meal at 1pm.
- Aiming to hit an appropriate protein intake (120g).
In this case, it probably is a slightly suboptimal approach for optimising training adaptations. Obviously,
the fact that you are 1) training and 2) eating sufficient protein in general are very significant contributors to the muscle building process, but you may be shortchanging yourself by not spreading that protein intake across the day, particularly around the training window.
Is this going to be a night and day difference? Probably not. However, it's a relatively good idea to consume protein around the training window at the very least,
as the process of training is acutely catabolic, meaning that it involves muscle protein breakdown. We are more sensitive to muscle protein synthesis after the fact, so having protein around the training window can help to 1) blunt that muscle protein breakdown and 2) support muscle protein synthesis.
Consume ~0.4 g/kg body mass (i.e., 0.24 plus 0.06 with protein added to account for the influence of other macronutrients in meals and protein quality), to maximally stimulate
MPS following a period of rest or exhaustive resistance exercise.
Spacing protein-containing meals ~3–5 h throughout the day maximizes MPS rates over the course of a 12 h (i.e., waking) period.
Practice pre-sleep protein ingestion (1–3 h prior to sleep) to offset declines in MPS that would occur during an overnight fasting period.
To maximize muscle protein accretion with resistance exercise, daily protein intakes should be ~1.6 g/kg/day and up to 2.2 g/kg/day. This intake can be achieved by ingesting 3 meals, each containing ~0.53 g/kg protein, or 4 meals containing ~0.4g/kg protein.
They are some nice guidelines to work off. You don't need to get too caught up in the whole "anabolic window" approach, whereby people feel the need to slam a protein shake
immediately after a workout, but having some protein when it suits you after a workout is a pretty good idea. If you eat a meal with protein prior to your workout, then it's less of a priority, but if you are training fasted, it is more important.
We hope that sheds some light on the topic. Fasting can be a great tool, but for those looking to really get the most from their training, having some protein around the workout period is probably a
good idea, not to mention the fact that eating prior to a workout is also likely to lead to more productive training in the first place. It just depends on the extent of your goals!
Kind Regards,
Gary & Paddy
Triage Method
