Do you need carbohydrates during training?

Short answer

For a typical lifting session of about 60 minutes, no. Carbohydrates during exercise mainly help in endurance work beyond 60–90 minutes. Guidelines then give 30–60 g per hour, and up to 90 g for sessions over 2.5 hours.

Figures

60–90 min · duration where it starts to pay off
30–60 g/h · for 1–2.5 h of exercise
up to 90 g/h · over 2.5 h, using glucose and fructose

For a lifting session of about 60 minutes, water is enough

Lifting

A 60-minute session does not empty glycogen stores. Evidence for a benefit of carbohydrates during such sessions is weak. Water is enough if you ate normally beforehand.

When it makes sense

For sessions over 90 minutes, very high volume, fasted training, or lifting plus endurance on the same day. A sports drink or a banana covers part of it; the exact amount is on the label or in a nutrition table.

Endurance

For 45–75 minutes of intense endurance work, small amounts or a mouth rinse are enough. Over 2.5 hours, up to 90 g per hour is possible if the drink combines glucose and fructose. Practise high intakes in training.

Sources

Burke et al. · 2011 · J Sports Sci DOI
Steps by duration: mouth rinse, 30–60 g/h, up to 90 g/h.
Thomas, Erdman, Burke · 2016 · Med Sci Sports Exerc DOI
Carbohydrate during exercise.
Kerksick et al. · 2017 · J Int Soc Sports Nutr DOI
Timing around resistance training.

Summaries by SetCtl, not medical advice.