Can a lubricant reduce fuel consumption?

Yes. Modern lubricants are required to be validated in tests certifying that they reduce fuel consumption or certain properties inherent to this characteristic are requested. Some of the manufacturer's specifications are especially inclusive on fuel economy, so this name is usually associated as part of the promotional claim.

Related questions:

• What are the differences between lubricants?
• How do greases differ from industrial lubricating oils?
• Why do engines consume lubricant? Can it be avoided?