DietDelta: A Vision-Language Approach for Dietary Assessment via Before-and-After Images

📅 2026-04-07
📈 Citations: 0
Influential: 0
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🤖 AI Summary
This work addresses the challenge of accurately estimating food types and portion sizes from a single pre-meal image, a task hindered by reliance on depth sensors, multi-view imagery, or explicit segmentation in existing methods. The authors propose a novel framework leveraging vision-language models that operates solely on paired pre- and post-meal RGB images, eliminating the need for segmentation masks or specialized hardware. By employing natural language prompts to localize food items and estimate their weights, and integrating a two-stage training strategy to compute intake, the method enables fine-grained dietary assessment. It represents the first application of vision-language models to paired mealtime images for food-level nutritional analysis and establishes a new state-of-the-art across three public benchmarks, setting a practical baseline for real-world dietary monitoring.
📝 Abstract
Accurate dietary assessment is critical for precision nutrition, yet most image-based methods rely on a single pre-consumption image and provide only coarse, meal-level estimates. These approaches cannot determine what was actually consumed and often require restrictive inputs such as depth sensing, multi-view imagery, or explicit segmentation. In this paper, we propose a simple vision-language framework for food-item-level nutritional analysis using paired before-and-after eating images. Instead of relying on rigid segmentation masks, our method leverages natural language prompts to localize specific food items and estimate their weight directly from a single RGB image. We further estimate food consumption by predicting weight differences between paired images using a two-stage training strategy. We evaluate our method on three publicly available datasets and demonstrate consistent improvements over existing approaches, establishing a strong baseline for before-and-after dietary image analysis.
Problem

Research questions and friction points this paper is trying to address.

dietary assessment
food consumption estimation
vision-language models
before-and-after images
nutritional analysis
Innovation

Methods, ideas, or system contributions that make the work stand out.

vision-language model
dietary assessment
before-and-after images
food weight estimation
prompt-based localization
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Gautham Vinod
Gautham Vinod
PhD Candidate in ECE, Purdue University
Computer VisionSmart HealthImage ProcessingDeep Learning
S
Siddeshwar Raghavan
Purdue University, West Lafayette, Indiana, U.S.A.
B
Bruce Coburn
Purdue University, West Lafayette, Indiana, U.S.A.
F
Fengqing Zhu
Purdue University, West Lafayette, Indiana, U.S.A.