Tuberculosis (TB) still poses a significant challenge to public health globally, especially in low- and middle-income countries such as Kenya. Despite the robust strategies, malnutrition remains a barrier to positive treatment outcomes, delaying sputum conversion. This study aimed to assess the effects of positive deviant nutrition intervention on sputum smear conversion among patients on Tuberculosis medication in Kericho County. A prospective study was conducted for patients enrolled on TB medication in both Bureti and Ainamoi Sub counties. A multistage cluster sampling was used to identify and recruit participants. The study was quasi-experimental, with a total of 192 sample units participating in the survey from the eight TB treatment catchment areas. Data was collected from January to December 2023 with sputum follow-up, a critical treatment period of six months. Data was analyzed using R 4.3.1 software. The sputum smear conversion rate for the intervention study and control arms was 96.8% and 85.2% in the 6th month, respectively. The results showed that the intervention arms demonstrated strong and significant associations between body mass index and sputum conversion at all three critical time points in 2nd month, 5th month, and 6th month with 29.51 p=<
0.000, 30.85 p=<
0.000, 35.19 p=<
0.000, respectively compared to their counterpart. Additionally, among the intervention group, energy intake was associated with significant optimistic estimates for sputum conversion at all critical time points, 0.76, p = 0.007: 0.86, p = 0.006: 0.91, p = 0.003 compared to those in the control group. Maintaining a better weight and consuming adequate energy were a significant factor in attaining a positive sputum conversion.