B737 flight crew reported excessive fuel consumption during cruise resulting in a diversion.

Attributes
ACN	1696117
Time
Date	201910
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Fuel System
Person 1
Function	First Officer
Qualification	Flight Crew Instrument Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 166 Flight Crew Total 1039 Flight Crew Type 1039
Person 2
Function	Pilot Not Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 127 Flight Crew Total 485 Flight Crew Type 485
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Weight And Balance Inflight Event / Encounter Fuel Issue

Narrative:

[During cruise]; crew noticed left fuel tank quantity decreasing slowly; but steadily with fuel remaining in the center tank.monitoring during cruise with reference to the operational flight plan did not indicate a fuel leak. However; the situation would eventually cause an imbalance. Additionally; the wing tanks are meant to be full with greater than 1;000 pounds in the center tank.due to the abnormal situation and after consulting with the company; the decision was made to divert to ZZZ. [ATC was advised] due to the aircraft exceeding an operational limitation and proceeded directly to ZZZ.an overweight landing to runway 1C was performed and the aircraft stopped once clear to allow for an external inspection to be performed by the aircraft rescue & fire fighting team.no defects were noted and the aircraft proceeded to the gate without incident.

Original NASA ASRS Text

Title: B737 flight crew reported excessive fuel consumption during cruise resulting in a diversion.

Narrative: [During cruise]; crew noticed left fuel tank quantity decreasing slowly; but steadily with fuel remaining in the center tank.Monitoring during cruise with reference to the Operational Flight Plan did not indicate a fuel leak. However; the situation would eventually cause an imbalance. Additionally; the wing tanks are meant to be full with greater than 1;000 pounds in the center tank.Due to the abnormal situation and after consulting with the company; the decision was made to divert to ZZZ. [ATC was advised] due to the aircraft exceeding an operational limitation and proceeded directly to ZZZ.An overweight landing to Runway 1C was performed and the aircraft stopped once clear to allow for an external inspection to be performed by the Aircraft Rescue & Fire Fighting team.No defects were noted and the aircraft proceeded to the gate without incident.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.