Long story short;
Collision induced muscle damage (CIMD) increases your total daily energy expenditure. This would suggest that the more contact you experience in a game, the greater the muscle breakdown and the greater need for calories to recover.
Short story long;
A pretty awesome study by Costello et al (2018) looked at how many calories you need extra per day if you have muscle breakdown from contact/collisions. In short, 6 pro RFL players completed condition (con) A for one week, followed by con B for another.
Con A = Contact training session at the start of the week + 4 normal days of training.
Con B = Non-contact training session at the start of the week + 4 normal days of training.
By doing it this way, any changes in energy expenditure will most likely be down to the collisions experienced at the start of the week. To make this a ‘real-world’ scenario, the players completed 20 collisions which somewhat resembles game day conditions.
By using the gold standard method for measuring energy expenditure (Doubly Labelled Water), the ‘contact group’ found that their calorie needs increased by 5% over a five day period. In addition to this, their contact rugby session RPE increased and their 5-day wellness (sleep quality, fatigue, muscle soreness, stress and mood) worsened.
So, not only does contact in rugby increase the amount of energy you expend for the following 5 days, it makes you a little crankier in the process.
This, most likely is due to the increased calorie demand of muscle protein synthesis (MPS) needed to repair and remodel the damaged muscle.
After a typical weight training session, MPS will increase for 24-48 hours to help repair the muscle, but in rugby players, the muscle damage is much higher and can last for 5 days. This would suggest that it’s probably quite important that you eat a little more (5%) after games and contact in training.
For those who are doing double contact per week, probably more again? Either way, if optimal recovery and performance is key, don’t restrict your calories in season.