Ask Dr Adam: Should I Eat Differently on Training Days vs. Rest Days?

Any gym-goer worth their electrolytes knows that fuelling effectively is the bedrock of seeing results from your training. From glugging enough water and carb loading first-thing, to consuming enough protein to support muscle growth, countless articles have talked about the importance of eating well to support big gym efforts.

But when it comes to rest days, the advice isn’t so front and centre. Should you continue strategically supping on protein shakes and loading up on complex carbs, or is it better to relax your usual eating habits and take a different approach?

To get the answers, we asked Dr Adam to explain how adjusting calories, carbs and protein between training and rest days can support performance – and how to do it without turning eating into a dull, finance bro-coded spreadsheet.

Do we need to adjust calories between training and rest days to account for extra movement?

Technically, yes – but in practice, it really depends on how much training you’re actually doing.

A standard gym session or spin class rarely warrants consciously increasing your calories. Energy balance doesn’t operate on a strict 24-hour cycle; it evens out over several days, so small deficits on one day are often naturally offset by slight surpluses on another.

However, if you’re training hard and frequently (for example, several hours of moderate to high-intensity exercise most days of the week) then increasing calories becomes important. You need to fuel adequately to support both performance, recovery and adaptation. That extra intake doesn’t necessarily have to happen entirely on the training day itself; it can be distributed across the days before and after.

Ultimately, the goal is to match your overall calorie intake to your overall energy expenditure across the week.

Research suggests we burn significantly more carbohydrates on intense training days. How should that influence carb intake?

This is a more nuanced question. On intense training days – particularly those focused on power, speed or maximum performance rather than endurance – you will burn through carbohydrates much more quickly. This is because the energy demand is higher, and you rely more on anaerobic metabolism, which breaks down carbohydrates around 15 times less efficiently.

Rather than focusing purely on absolute grams of carbohydrates, the priority should be starting these sessions with fully topped-up glycogen stores. If you are doing multiple sessions in a day, you should also try to replenish those stores between sessions.

In practice, this may mean having a carbohydrate-containing meal a few hours before training, and possibly a higher-carb dinner the night before if you are training early. A good rule is to make sure carbohydrates are included in meals throughout the day – but avoid relying solely on quick-fix, high-GI options such as sweets, bars, drinks or gels.

Should protein increase on harder training days?

The short answer is yes.

This is not only because of the need to repair and build muscle, but because protein is also required to support adaptations to endurance exercise, such as repairing and producing new mitochondria and improving blood supply.

Higher-intensity exercise, particularly resistance training, stimulates increased protein synthesis to repair and create new myofibres in our muscles. Over time, this can lead to muscles that are more densely packed with fibres and potentially larger overall, resulting in greater strength, power or speed.

That said, protein feeding doesn’t need to be confined to a narrow ‘anabolic window’ immediately after exercise. Simply ensuring you’ve got enough protein intake across the day – including in pre- and post-exercise meals – is sufficient. A protein shake can help to make sure your total intake is enough.

Can adjusting food intake help you reach body composition goals faster?

Yes – both in terms of calories and macronutrient distribution.

On lower-intensity or rest days, reducing carbohydrate intake can be a sensible strategy. Some athletes also experiment with occasional ‘train low’ sessions. This involves deliberately limiting carbohydrate before or after certain workouts, to enhance fat oxidation and metabolic adaptations.

However, if fat loss is your primary goal, a consistent calorie deficit is essential.

For body recomposition (aka, reducing fat while maintaining or increasing muscle) combining resistance training with eating enough protein intake is key. Higher overall protein may help preserve (and potentially build) lean mass while body fat decreases.

What’s a simple way to fuel smarter on training vs. rest days?

Think of it simply as fuel for the work you’re doing.

On rest or lower-intensity days, you may want to reduce carbohydrates and slightly reduce calories overall, allowing your fuel stores to dip.

On harder or high-intensity training days, you’ll want to begin with full fuel stores by increasing your carbohydrate intake. This might require eating in preparation for those sessions, or during them if they’re long. 

In any and all cases, make sure you’re eating enough protein – not just on the training day itself, but also potentially the day after, to provide the building blocks needed for recovery and adaptation. 

The bottom line is that you don’t need to micromanage every gram. The aim is simply to match intake to output over time.