Enhancement of In-Store Product Replenishment Flow and Introduction of Pull Approach in a Food Retail Chain

Abstract

Background: Due to the highly competitive nature of the retail sector, companies need to improve their operational efficiency. This study focuses on the application of the concepts of Lean production in the process of replenishing products on the shelves of the shops of one of the largest food retail chains in Portugal. Methods: This study aims to apply a transition from a “push” to a “pull” approach, based on real-time consumption. During a 5-day test, the impacts of implementing Lean principles and ergonomic trolleys in the process were investigated. Results: The test led to improved efficiency in product replenishment by eliminating pallets and reducing unfavourable product handling from the initial process. The implementation of a replenishment system in this manner allowed a reduced labour requirements from 28.4 to 19.2 man-hours per day and, the elimination of unnecessary handling and increase of product availability were reflected in gains on operational time and in replenishment time. Conclusions: This study provides empirical evidence for the effectiveness of Lean pull systems in retail replenishment, demonstrating a 32% reduction in labour hours.

1. Introduction

The food retail sector is facing growing challenges due to intensified competition and increased consumer expectations regarding the availability and quality of products [1]. In this context, operational efficiency plays a key role in customer satisfaction and company sustainability. To meet these demands, many organisations have been adopting Lean methodologies, originally developed in the manufacturing industry, with the aim of eliminating waste and improving processes [2,3,4].

The Lean Methodology, a concept structured by Womack & Jones in 1996, is based on five fundamental principles: identify value, map the value stream, create flow, establish pull and seek perfection [5]. These principles have been widely applied in industry and supply chains, but their use to improve the internal flow of product replenishment on the shelves of food retail shops is still little explored [3,6].

Currently, many food retail shops use a replenishment process based on a push approach, in which products are taken to the sales floor to be replenished on the shelves according to their arrival at the shop’s warehouse, without considering the actual need for consumption. This approach results in long replenishment times for some products, unnecessary movement of products that didn’t need replenishing that return to the warehouse and out-of-stocks (OOS), factors that compromise both staff productivity and the customer experience. Given this scenario, it is essential to understand what the main weaknesses of this process are and how an alternative approach, based on the lean principles such create flow and establish pull, can help to improve operational efficiency, reduce operator effort and increase the availability of products on the shelves.

To answer these questions, this study adopts an action research approach and analyses the internal replenishment flow in one of the largest food retail chains in Portugal. After a detailed analysis of the current state of replenishment process, a new replenishment approach was developed and tested in line with the principle of operational fluidity, promoting a transition to a pull replenishment approach, where products are replenished based on actual consumption, reducing waste and improving the efficiency of the process.

The implementation of the new procedure included adjustments to the shop’s internal replenishment flow, the introduction of ergonomic tools to make the operators’ work easier and the standardisation of replenishment activities. During a five-day trial period, data was collected through direct observation, measurements of the labour hours, the number of OOS replenished, the average waiting times for replenishment and the pallet handling. The final evaluation was based on this performance metrics, and it was possible to observe a reduction in the number of the labour hours allocated to replenishment, an increase in the availability of products on the shelves and a reduction in the average waiting time for replenishment.

Although the Lean philosophy has been widely studied in industrial environments, its application to optimising the internal flow of product replenishment in food retail shops still lacks detailed empirical evidence. By investigating the impact of the transition from a push to a pull approach in this specific context, this study contributes to filling this gap and provides valuable insights for companies looking to improve their internal logistics processes.

2. Literature Review

The literature review was conducted to identify relevant studies on the efficiency of product replenishment processes in retail, with a particular focus on the transition from a push to a pull system. To ensure a comprehensive search, we employed a structured approach using key terms relevant to the topic.

The search was carried out in Scopus databases, and the selected articles were assessed based on their relevance and applicability to the study context. Additionally, we utilized the cross-referencing method, where articles initially identified led to further relevant studies through the examination of their cited references. This approach allowed for the inclusion of widely acknowledged research in the field, ensuring a robust and up-to-date theoretical foundation.

The review process prioritized both classic studies on Lean and replenishment systems as well as recent publications investigating the implementation of Lean methodologies in the retail sector. This ensured that the research was grounded not only in established theoretical frameworks but also reflected the latest trends and innovations in retail logistics.

2.1. Origins and Evolution of Lean Thinking

The origins of Lean thinking are deeply rooted in the Toyota Production System (TPS), developed in the mid-20th century by Taiichi Ohno and Eiji Toyoda at Toyota Motor Corporation [5]. TPS emerged as a response to the inefficiencies observed in mass production systems and focused on eliminating waste, improving flow, and enhancing value creation from the customer’s perspective [5,7]. The foundational principles of the Toyota Production System include just-in-time production, Jidoka or automation with a human touch, continuous improvement referred to as kaizen, and respect for people [8]. These principles laid the groundwork for what would later be known globally as Lean. The term “Lean” was formally coined by Womack, Jones, and Roos in their work [9], which documented the success of Japanese automotive manufacturing practices compared to Western models. This publication catalysed the global diffusion of Lean beyond the automotive sector. Subsequent works such as “Lean Thinking” by Womack & Jones [5] further distilled Lean into five core principles: define value, map the value stream, create flow, establish pull, and seek perfection.

Over time, Lean evolved from a set of production tools into a comprehensive management philosophy centred on achieving operational excellence [10]. Depending on the context, this philosophy is referred to as Lean Manufacturing [11,12], Lean Management System [13], Lean Construction [14] or simply as part of broader Operational Excellence models [15,16]. The integration with Six Sigma methodologies gave rise to LSS, combining Lean’s emphasis on waste elimination with the statistical rigour of Six Sigma for process control and defect reduction [17,18]. Its principles have been applied across various sectors, including services, manufacturing, automotive, and retail [19].

Lean has also intersected with Agile manufacturing [20], especially in software development [21] through frameworks such as Lean Software Development, which adapts Lean principles to iterative and customer-driven product development [22,23].

These evolutions demonstrate Lean’s adaptability across different organisational contexts and its continued relevance in environments seeking operational excellence, customer satisfaction, and sustainable value creation.

2.2. Practical Applications and Limitations of Lean in Retail Supply Operations

This literature review was conducted to identify relevant studies on the efficiency of product replenishment processes in retail, with a particular focus on the mail lean concepts and lean tools referred.

The adoption of lean principles in retail began in the 1990s, with companies like Walmart, Tesco, and IKEA becoming leading examples of its application. Lean retailing aims to improve the speed and efficiency of product flow to customers, enabling faster shelf replenishment and improving point-of-sale performance. In other words, it is necessary to improve retail value flows through ‘pull’ replenishment strategies, thus ensuring high levels of product availability [24]. Another case is Seven-Eleven Japan, where the application of lean principles in retail has been successful, achieving higher service levels, increased sales and reduced inventory through integrated process improvements [25].

The earliest Scopus-indexed article on lean thinking in retail examined inventory reduction as its primary focus [26] and numerous subsequent studies have been published and since then many other studies were published. The application of Lean thinking in the retail sector has gained considerable attention in recent years. Originally developed within the manufacturing context—specifically the Toyota Production System—Lean principles have evolved and found relevance in a wide array of industries, including logistics, e-commerce, and food retail.

To ensure a comprehensive search, we employed a structured approach using key terms relevant to the topic. The prompt used in Scopus database was the following: (kaizen OR “operational excellence” OR “lean production” OR “lean manufacturing” or “lean thinking” or “lean six-sigma”) AND (“retail sector” OR “retail company” OR “retail industry” OR “retail market” OR “retail business”). The search yielded 29 publications, of which 7 were excluded due to misalignment with our research objectives. Additionally, we utilized the cross-referencing method, where articles initially identified led to further relevant studies through the examination of their cited references. This approach allowed for the inclusion of new 4 article. The result is 26 relevant publications are summarized in

Table 1. Main lean tools and concepts presented in the literature.

Lean Tool/Concept	Publications
Kaizen	[27,28,29,30,31,32,33]
Value Stream Mapping	[29,30,32,33,34]
DMAIC	[33,34,35,36]
Lean in general	[37,38,39,40,41,42]
Kanban	[33,43,44,45]
5S	[31,33,43]
Operational Excellence	[46,47]
Andon	[43]
Pull concept	[31,37,38,48]
Agile Project Management	[49]

, categorized by their referenced lean concepts/tools.

Although that was the result of our search, according to Jimenez et al. [30], the literature identifies JIT, VSM, 5S, Poka-Yoke, and Kaizen as the most common Lean tools used in retail and supply chain management. A related study [33] identified a broader range of Lean tools applied in retail, with VSM and Lean Six Sigma being the most prevalent, followed by Lean Thinking, Lean Production Design, Lean Supply Chain, and finally Hoshin Kanri, Kaizen, and Kanban.

Regarding the concept of non-value adding activities or waste as well as its identification in the retail sector, several publications can be found in literature. Lukic [50] is an example presenting a classification proposal for waste types, but there are others [51].

In the context of inventory and replenishment management, Lean methodologies have been used to address out-of-stock events, inefficiencies in stock handling, and poor on-shelf availability [25,28,52]. For example, Lean initiatives have successfully improved operational performance in supermarkets and hypermarkets, particularly by redesigning warehouse layouts, restructuring restocking workflows, and applying visual inventory management systems [3]. These changes not only improved the order fulfilment rate but also contributed to waste reduction, higher service levels, and better integration with e-commerce operations.

Other researchers have combined Lean principles with sustainability objectives, demonstrating how practices can reduce food waste, support circular economy initiatives, and improve environmental metrics such as carbon footprint [25,53]. Furthermore, Mollenkopf et al. [48] explore the synergies between lean practices and sustainability in global retail operations.

On the other hand, Lean Six Sigma has been applied in retail environments to enhance process control, quality assurance, and compliance with food safety standards [54]. The integration of Lean tools with DMAIC methodology has proven particularly effective in identifying bottlenecks, eliminating non-value-adding activities, and improving overall equipment effectiveness (OEE) [54].

Technology has also become an essential enabler of Lean in the retail sector [40,55]. Some studies highlight the role of real-time data, AI-powered forecasting, and even social media analytics in enhancing inventory accuracy and customer satisfaction [56,57,58,59]. In this light, new approaches that combine Lean Software Development (LSD), Agile project management frameworks (e.g., Scrum), and Lean Startup principles are also being tested in smaller retail settings and digital environments, such as financial and stock control applications [60,61].

The literature highlights that although Lean, Six Sigma, and AI-based inventory optimisation have been widely applied across supply chain and retail contexts, there is a noticeable lack of empirical studies specifically addressing the transition from Push to Pull replenishment systems within store-level operations. Most research has focused on upstream supply chain improvements or warehouse optimisation, often overlooking the practical challenges of in-store replenishment.

This study addresses the following research gaps:

• A scarcity of empirical evidence evaluating Pull-based replenishment in supermarkets, particularly regarding its effects on operational efficiency and labour resource allocation. While works such as the work from Guimarães et al. [3] and from Marques et al. [28] investigate in-store logistics, few provide quantifiable insights into this specific transition.
• Limited exploration of integrating Lean methodologies with real-time inventory tracking, a key factor in reducing stockouts and improving on-shelf availability. Although Lean has shown success in broader distribution and e-commerce settings [29,36,53], its application at the shelf level remains underdeveloped.
• Underrepresentation of ergonomic and workflow impacts in existing studies on Lean in retail. Despite evidence of reduced waste and improved labour time [3,25], the specific effects on employee well-being and task efficiency have not been sufficiently explored.

This study contributes to filling these gaps by delivering practical, data-driven evidence of how Lean principles—especially the pull approach and continuous flow—can improve in-store replenishment processes. It further expands the discussion on the operational and ergonomic implications of Lean in retail environments, beyond traditional warehouse-centric applications.

3. Methodology

The study was carried out in one of the largest food retail chains in Portugal, as part of an innovation project in partnership with the research team, centred on the process of replenishing products on the sales board shelves. The research team comprises industrial management engineers, specialists in Lean, and the intervention was carried out in nine food aisles of a small shop in this supply chain.

To achieve the objectives set for this study and given the involvement and active participation of the research team in the problem, an Action Research strategy was adopted [62]. This strategy involves a cycle of five phases (Figure 1): diagnosis, planning, implementation of actions and, finally discussion and evaluation of the actions results, based on action research spiral [63].

In the diagnostic phase, referred to as ‘Understanding the current state’ in Figure 1, the main process inefficiencies were identified from direct observations, as well as some performance measures. Other performance measures were obtained from existing data provided by managers. In the diagnosis phase, referred as “Grasp the current condition” in Figure 1, the main inefficiencies in the process were identified and performance metrics were collected both from existing data and through direct observations. These observations were initially carried out randomly and then the replacement employees were fully monitored. The existing data and collected data were analysed, and the research team began to outline improvement actions that led to the new procedure based on the principles of create flow and establish pull of Lean Methodology Philosophy (two classical principles of Lean Thinking [5]). In this phase the research team was working with shop managers and employees to devise consensual transformations towards a new replenishment standard.

In the planning phase, the research team met with shop management and the employees defined an action plan that could deal with all involved in this process to analyse the data collected and propose a new replenishment approach existing restrictions related to the normal shop routines.

Subsequently, to implement the new procedure, as a test, training sessions were held with employees to define and adjust all aspects of the new procedure. Aspects of the procedure were tested on a one-off basis, with certain products at different times, so that all the adjustments necessary for implementation could be made. Several cycles were carried out to define actions until the final proposal and testing of the new procedure over a period of five days.

4. Results

The results of this study are demonstrated in this section, which contains the characterization of the initial situation, the description of the changes introduced, and the main conclusions obtained with the change in the procedure.

4.1. Initial Situation: “Push” Approach

Before the intervention, the “push” configuration presented several inefficiencies that compromised productivity and the effectiveness of replacing products on the shelves. The process, illustrated in Figure 2, begins with the arrival of pallets, containing mixed products, of large dimensions (up to 220 cm in height) at the store warehouse. According to the gathered data, around 57% of pallets can exceed 1.80 m in height and around 18% of total pallets can reach heights of more than 2 m, reaching a maximum height of 2.20 m. The next step involves breaking down these pallets so that the products can be subsequently sent to the shelves where they are needed. During the depalletizing, the products are distributed onto new pallets to be taken to the store based on the location of the products in their respective aisles, regardless of the actual need for replenishment of each product—a “push replenishment” approach. Since all products are transported to the store aisles without knowledge of the specific products and quantities needed, it is common for many products to be transported back to the warehouse. A study carried out during the diagnostic phase revealed that around 30% of products transported from the warehouse to be replenished on the shelves are returned to the warehouse because there is no room for them on the shelves.

Pallet arrival and the depalletizing process occur during the day, while the store is open, however, most replenishment tasks are performed at night when the store is closed. This practice leads to several inefficiencies, such as increased product handling, additional transportation and storage rework, consequently decreasing the overall efficiency of the replenishment system. Furthermore, since the massive replenishment activities only takes place before the store opening, it creates very long time periods without replenishment, leading to OOS incidents. Throughout the rest of the day, however, the operators continue to perform replenishment tasks, focusing primarily on addressing OOS situations and other needs that arise during open hours. The gap between the arrival of products and their availability on the shelves can be up to 15 h.

Likewise, this system of placing products on shelves without a precise analysis of real replacement needs inhibits any possibility of standardizing processes, leading to products being transported to the store that later return to the warehouse to be stored again. One of the perceptions during the analysis was that items that are out of stock on the shelf can take around 9 h on average to be replenished. In other words, the product is missing from the shelf and is replenished around 9 h after it has arrived in warehouse. This is because products often arrive and wait in the backroom, without going straight to the shelf.

Figure 3 shows the average time of one working day for this process. Thus, an average of 28.40 man-hours is typically allocated, of which only 17.50 man-hours are spent restocking shelves. An average of 5.75 h of unplanned breaks were observed, which mostly included help with other activities in the store and absences.

4.2. Intervention: Implementation of the “Pull” Mechanisms

The proposed solution to these issues involves transitioning to a pull replenishment approach, where products are continuously restocked based on actual consumption needs. The core objective of Lean retailing is to achieve optimal retail operational efficiency by focusing on two key elements: shelf availability and efficient product flow. As shown in Figure 4, this requires establishing quick and rhythmic movement of goods towards the shelves while maintaining consistent product availability for customers.

Through careful management of these components, retailers can enhance their value-added operations across the supply chain. This approach emphasizes maintaining high shelf availability through “pull” replenishment strategies, while ensuring efficient, quick, and rhythmic product movement, meeting customer needs and maximizing operational value.

This reduces unnecessary movement and improves product availability on shelves, ensuring that only necessary items are transported from the warehouse to the store. Not only does this reduces returns to the warehouse, but it also improves product flow, leading to smoother operations and a more demand-driven approach. Likewise, we propose the introduction of a reordering point and OOS detection system to identify the real replacement needs, the proposed pull approach process is represented in Figure 5.

In the absence of an OOS detection system, as it is a technological solution that is not currently available, during the experimental period the identification of OOS was carried out manually by employees in parallel with the replenishment process.

From this context, based on the concept of continuous flow and the need to have the product on the shelf available sooner for the customer, work was done to develop a new work procedure, as we can see the macro stages in the flowchart in Figure 6.

Based on the analysis carried out, the team identified the need to improve and standardize the procedures of the processes under analysis. New procedures were then developed for a new process flow to make the replenishment processes more efficient and also less demanding for the operators in terms of effort, which included defining new techniques, working practices and integrating equipment to facilitate this process.

This solution was tested over a 5-day trial period. In order to apply the new procedure, the process operators were trained to understand the concept of pull flow and to prioritize the replenishment of products that were in greatest need of replenishment, rather than replenishing them randomly and at specific times. To carry out the experiment, a roadmap was created with the main steps of the new process Figure 7. These steps were presented to employees so that they could remember the stages and the main activities in each.

The new procedure involved manual aisle checks to identify products requiring replenishment before the pallets were opened, necessary to a pull replenishment approach.

To deliver value to the customer as quickly as possible, a Just-in-Time approach was adopted: incoming pallets were dismantled one at a time and the products were immediately placed at their destination (warehouse or store shelves). This eliminates the need for inter-mediate inventory and makes the process simpler and more efficient, in line with Lean principles. Therefore, the process of sorting the products was eliminated, taking away from the employees the constant decision making to place the products on the correct pallet and eliminating the wait for replenishment after the store closes.

Before the pallets arrive from the Distribution Centre, the team checks to see if any products need to be replenished on the shelves. In this way, it is possible to create a list of products that need to be replenished as a priority when they pick up the products from the newly arrived pallets or from the warehouse. Additionally, after the unloading, a document is printed detailing the products on each pallet that are in OOS situation in the shelves, further establishing an order of priorities for the replenishment activities.

To simplify the handling and transportation of products, replenishment trolleys were added to the process Figure 8. Each trolley is loaded with products in the order they were arranged on the original pallet, making it immediately operational for replenishment.

Products not needed in the shelves are transported to designated locations in the warehouse, while the others are stay in the trolley to be transported to the store shelves. Unlike in the past, when incoming products were distributed on pallets, one for each destination aisle, products are now placed on the trolley in the sequence in which they are removed from the supplier’s pallet. The trolley then makes its way through the aisles of the shop, replenishing the products in each aisle it passes through. Replenishment occurred continuously during both open and closed-store periods, with a total operational time of 19.20 man-hours, as shown in Figure 9.

Additionally, replenishment trolleys were considered more ergonomic to replace pallet trucks with pallets, as pallet trucks required operators to perform ergonomically unfavourable movements.

With a total allocated time of 22.50 man-hours, 3 h of unplanned breaks per day, 3.30 h of organization, storage and preparation of trolleys were identified. Approximately 12.90 man-hours are used to replace products. All times represented refer to the daily average during the experimental period.

Based on the intervention described, the process improvement can be summarized in three main areas that should be considered:

i.

Operational gains: the intervention focused on refining and adjusting the process to increase operational efficiency, which was validated through time improvements. By transitioning from a “push” to a “pull” replenishment system, we reduced unnecessary handling and transportation, which resulted in a decrease in the number of daily working hours from 28.40 to 19.20. This time saving of approximately 32%, demonstrates the reduction in resource requirements and the elimination of excessive movements, such as sorting pallets, disposing of cardboard, and operating pallet trucks. There was also an elimination of transport and movements related to the returning of products to the warehouse. The improvement has also minimized unproductive tasks, showing a leaner and more efficient process, with fewer delays and optimized resource allocation.

ii.

Service level: getting products on the shelves in less time and with a wider range of items has allowed us to respond better and faster to customer needs. Switching to a pull approach increased the availability of products on the shelves during store opening hours, providing a faster response to customer needs. The results of a study carried out in the cereals aisle showed an estimated 64% improvement in the availability of products on the shelves, as well as a 15% reduction in the waiting time to replenish each item (measured by the indicator “Average waiting time to replenish each missing item”). These changes ensure that customers are faced with fewer stock-outs and more readily available products, directly improving their shopping experience and satisfaction.

iii.

Team adaptation needs: implementing a new replenishment method requires the team to adapt to the new workflow and responsibilities, which can be a challenge. This trans-formation of the process can generate resistance as employees adapt to different tasks and routines, especially when incorporating new techniques and equipment, replenishment at various times of the day and the use of ergonomic trolleys. Managing this transition is important to ensure that the team fully adopts the “pull” replenishment approach. Training has been provided to help operators understand the concept and prioritize based on product needs, but ongoing support and communication is crucial to minimize resistance and support long-term adoption of the new procedures.

These three pillars—operational efficiency, service level improvement and team adaptation—have collectively contributed to a more effective replenishment process.

5. Discussion

The intervention of changing from a “push” to a “pull” replenishment approach resulted in significant improvements in efficiency and ergonomics. The reduction in daily man-hours from 28.40 to 19.20 demonstrates substantial savings in time and resources. This improvement can be attributed to the elimination of excessive handling and transportation, as well as the improvement of product flow based on real consumer consumption, as also demonstrated in the work of Guimarães et al. [3].

The introduction of ergonomic trolleys has not only improved efficiency but also provided significant improvements in ergonomics and satisfaction benefits for operators. The reduction in unfavourable movements and ease of use of the new trolleys contributed to a safer and more comfortable working environment, as evidenced by positive feedback from operators. Figure 10 presents the main performance indicators analysed in this study. The differences between the two shelf replenishment approaches are presented for the different metrics analysed and the gain obtained after the intervention.

During the intervention, it was possible to observe gains of around 28% in operational time and 26% in replenishment time (see Figure 11). These reductions are closely linked to the decreased need for resource-intensive activities. Aligning with findings from VSM-based retail improvements reported in literature, these indicators show the lower need for resources to execute the process [28,64]. The elimination of separating pallets, trips to discard cardboard, and movements with pallet trucks has contributed significantly to these results, by reducing non-added value activities.

Other operational benefits include the reduction in unnecessary trips to the store due to better alignment between stock levels and actual consumption. Furthermore, the transition to a “pull” system increased shelf availability during store opening hours, enabling more immediate customer service. This was evidenced by a 64% increase in the number OOS items replaced per day, an indicator often highlighted in the literature as essential for evaluating retail efficiency and customer service [6,52].

The continuous presence of operators in the store area facilitated the timely detection and replenishment of out-of-stock items, resulting in a 15% reduction in the average waiting time to restock each missing item.

Although Lean and pull production have been studied in the context of broader supply chain and warehouse operations, there is limited empirical evidence concerning their direct application within in-store processes. This study addresses that gap by providing concrete results from a food retail environment, demonstrating how Lean principles can enhance the efficiency and ergonomics of shelf replenishment activities.

The results have several practical implications for the food retail sector. Adopting a “pull” replenishment approach can be an effective strategy for other stores and retail chains looking to improve operational efficiency and employee satisfaction. Additionally, ergonomic improvements highlight the importance of considering operators’ health and well-being when implementing process changes, which can prevent long-term workplace illnesses.

Despite the improvements observed, the implementation of the “pull” approach presented challenges, particularly related to operator training. The initial learning curve may have temporarily impacted productivity, but the results indicate that, over time, operators adapted, and efficiency increased. In addition, the way the warehouse is structured, considering the use of pallets, presents some challenges in storing products and identifying their location when they are needed.

6. Conclusions

This study examined the implementation of a “pull” replenishment approach in one of the largest food retail chains in Portugal, replacing the traditional “push” replenishment model. The application of Lean principles, which are centred on the elimination of waste and the maximisation of customer value, proved highly effective in enhancing operational efficiency and improving working conditions for store operators.

The transition to the pull approach resulted in a substantial reduction of approximately 9.2 labour hours per day. This efficiency gain is primarily attributed to the elimination of non-value-adding activities such as excessive handling, transportation, and unnecessary pallet movements. The introduction of ergonomic trolleys has also been demonstrated to reduce physical strain and enhance operator satisfaction.

Consequently, the implementation of the pull-based replenishment system was identified as a pragmatic and efficacious strategy for enhancing operational performance, reducing waste, and promoting ergonomic improvements in the context of food retail. These findings underscore the importance of aligning replenishment activities with real-time consumption data and Lean principles.

Looking ahead, further advances in digital technologies—particularly real-time inventory tracking and automatic out-of-stock detection systems—are essential to fully optimise pull systems. The integration of such tools could improve replenishment accuracy, reduce human error, and enable more proactive responses to stockouts. It is recommended that future studies explore the impact of these digital enablers in diverse retail contexts and over longer periods to consolidate the evidence base for sustainable, data-driven Lean retail practices.