Eating on rest days.

A little less energy, not a lot

A rest day uses a little less energy than a training day, not a lot less. Going by the activity values in the Compendium of Physical Activities (Ainsworth, 2011), a 45 to 60 minute lifting session costs an 80 kg person very roughly 150 to 400 kcal above resting, and resting energy use stayed about 5% higher for up to three days after one full-body session (Heden, 2011).

So a rest day needs a little less food, not a different diet, and what counts for your body is the average across the week. Intermittent and continuous calorie cuts gave similar results (Cioffi, 2018), and in trained lifters, planned diet breaks matched continuous dieting with less hunger (Peos, 2021).

Protein stays the same

Protein stays the same on a rest day. Muscle keeps building for about a day after training, and the daily total is what counts most (see what rest days do for muscle). Your plan already keeps the protein target the same every day.

Snacks and sweets

There are no good or bad foods in a plan, only how they fit. Sugar changes body weight through the calories it brings: swapping sugar for other carbohydrates at the same calories did not change weight (Te Morenga, 2013). Some foods fill you up more than others at the same calories. Foods rich in protein, fibre and water filled people most, pastries least (Holt, 1995), and sugar in a drink was not made up for by eating less later, while the same sugar as a solid snack was (DiMeglio, 2000).

A flexible way of eating, rather than strict rules, goes with less overeating and keeping weight off in surveys (Westenhoefer, 1999; Westenhoefer, 2013; Smith, 1999), and in a ten-week trial with trained adults a flexible plan and a strict one gave the same fat loss (Conlin, 2021). If food and guilt go together for you, a registered dietitian or a doctor can help.

Rest days in your targets

If you chose separate targets for training days and rest days at setup, a rest day has fewer calories and the same protein; otherwise every day has the same targets. Today and the food diary show the day's target.