Chapter 1 presented the background of the thesis and stated this thesis aimed to gain insight into weight management in people with SCI with a specific focus on body composition and resting energy expenditure (REE). Chapter 2 presented the changes in body composition during and up to one year after inpatient rehabilitation in people with SCI. A relatively stable body composition, with among others no significant changes in the percentage of FM (FM%) and FFM (FFM%), was found during inpatient SCI rehabilitation. This was followed by a significant increase in BMI during the first year after discharge. Chapter 3 presented the accuracy of bioelectrical impedance analysis (BIA) and skinfold thickness measurements relative to DXA in estimating body composition. Furthermore, new prediction equations to estimate FFM and FM% in people with SCI were developed. As expected, BIA and skinfold thickness measurements could not be utilized directly to estimate body composition in people with SCI because of their low accuracy. Therefore, new SCI-specific body composition equations were developed using the outcomes of BIA or skinfold thickness measurements. The new equations for predicting FFM and FM% showed good levels of explained variance (R2 = 0.66 – 0.94). Chapter 4 presented the accuracy of two recently developed SCI-specific REE equations and the development of new REE prediction equations in people with SCI. The accuracy of the recently developed SCI-specific REE prediction equations by Chun et al. and by Nightingale and Gorgey may not accurately estimate REE in a general population of SCI. This might be because they were developed in people with motor complete injury under a stricter testing procedure. Using the outcomes of body composition measured by BIA or skinfold thickness, we developed new SCI-specific REE equations in a general population of SCI. However, the accuracy of the new equations did not meet our expectations. Chapter 5 and 6 presented the results that focused on whether using NMES of paralyzed lower-limb muscles increases energy expenditure during daily activities in people with SCI. We found in chapter 5, in people with SCI during sitting, that using the most intense NMES protocol with more muscles activated and the duty cycle with a shorter rest period resulted in a 51% increase in energy expenditure compared to the condition without NMES. Similarly, in chapter 6, we found that the energy expenditure significantly increased by wearing an NMES garment on paralyzed upper-leg muscles during 20-min lying (+29%) and sitting (+22%) but not during wheelchair propulsion (+8%) when participants were asked to perform the activities as they normally would instead of sitting still like in chapter 5. Chapter 7 combined the findings of this thesis and discussed the results from scientific and clinical perspectives. Monitoring body composition at least annually with accurate and feasible measurements is necessary together with ongoing management in daily life by surrogate markers such as BMI and waist circumference. The reliability of BIA and skinfold thickness should be tested, and the newly developed SCI-specific body composition equations need to be cross-validated before implementing in clinical practice. If there are adverse changes in body composition, REE should preferably be measured by clinically feasible indirect calorimetry devices to prescribe necessary interventions. Using NMES of paralyzed lower-limb muscles is a very promising method to increase energy expenditure in people with SCI. Personalizing optimal NMES parameters to achieve a better efficacy and adjusting the NMES garment to make it more suitable for people with SCI will help them achieve a healthy energy balance much easier in daily life and subsequently contribute to reaching their personal goals of weight management.