Food sales increased in February but overall Scottish sales declined year-on-year by 1.9%.
The Scottish Retail Consortium (SRC) said 2017 had "got off to a somewhat sluggish start" following a second successive month of falling sales.
It suggested consumers were responding to a combination of moderate wage growth and rising overall inflation.
SRC director David Lonsdale said: "In recent months we've seen a polarisation in the performance of food and non-food categories, which continued in February.
"Food sales continued to edge up, helped by good sales of wine and chocolates for St Valentine's Day as well as stronger demand for grocers' meal deals, which perhaps hints at less eating out during the period as consumers reined in spending.
"By contrast, non-food categories fell back once again, particularly clothing, footwear and household appliances, though there was continuing interest in mobile phones, wearable technology and a revival in gaming products."
He added: "These figures suggest Scottish consumers are maybe beginning to tighten their belts and acknowledge the strain from rising overall inflation and moderating wage growth, with council tax set to creep up soon too."

Gibbs had the upper hand and was serving at 7-5 2-6 2-1 when the players were called off on Sunday evening.
Their match will resume on Monday following the conclusion of Grigor Dimitrov's contest against Viktor Troicki, which was due to start at 10:00 BST on court three, but has been delayed by heavy rain in Paris.
Kyle Edmund was among a host of players scheduled to begin their campaigns on day one but who must now wait on the weather.
Edmund will now be third on court six against qualifier Nikoloz Basilashvili, while fellow Briton Naomi Broady plays Coco Vandeweghe on court four.
British number one Andy Murray is scheduled to face 37-year-old Czech Radek Stepanek in the fourth game on Philippe-Chatrier Court, but, with more rain expected, it is likely they will play on Tuesday.
Australian Nick Kyrgios and two-time Wimbledon champion Petra Kvitova both progressed before the rain delays on Sunday.
Kyrgios overcame a first-set code violation to beat Italy's Marco Cecchinato 7-6 (8-6) 7-6 (8-6) 6-4.
The men's 17th seed picked up the warning for screaming at a ball boy for a towel during the first-set tie-break and then accused umpire Carlos Ramos of "unbelievable bias" for his punishment.
Tenth seed Kvitova needed three sets to get past Danka Kovinic of Montenegro 6-2 4-6 7-5.
Lucie Safarova, last year's losing finalist, breezed through to the second round with a 6-2 6-0 victory over Russia's Vitalia Diatchenko.

The West Indies all-rounder also described WICB president Dave Cameron as "arrogant" and "very immature".
West Indies won the World Twenty20 by beating England in a dramatic final on Sunday.
But Bravo, 32, says his team turned up for the tournament without their kit being ready and says they played the entire event without caps.
"We get to India, our names were not even printed on the uniforms," he said. "Our manager had to leave our camp to get names and numbers printed."
Media playback is not supported on this device
The comments will do nothing to ease the tension between players and the WICB, who are already in involved in a long-running pay dispute.
T20 captain Darren Sammy also criticised the WICB during the post-match presentation after his side's thrilling four-wicket win over England in Kolkata.
Bravo told CNC3, a Trinidad and Tobago television channel, that the players faced a lot of criticism in the run-up to the World Twenty20 tournament.
"A lot of people come down on the players," he said. "They questioned our commitment. They questioned whether we really committed to West Indies cricket or is it just the money.
"A lot of people don't understand the sort of thing we go through as players dealing with our board."
Scottish retail sales fell last month as consumers started to "tighten their belts", according to new figures.
[NEXT_CONCEPT]
Britain's number two Heather Watson fought back against American Nicole Gibbs at the French Open before play was suspended because of rain.
[NEXT_CONCEPT]
Dwayne Bravo has described the West Indies Cricket Board (WICB) as "the most unprofessional" in the world.