Excessive consumption of lipids is one of the major reasons for the prevalence of obesity. Interfacial engineering of food emulsions is highly expected to control the digestion and absorption of lipids, consequently to inhibit adipose expansion. However, this strategy is restricted mainly due to the lack of effective food emulsifiers. In the present study, the mung bean protein fibrils with short worm-like morphology were demonstrated to have superior capabilities than the mature ones in stabilizing high internal phase emulsions (HIPEs) and consequently inhibiting the lipid digestion to control in vivo adipose accumulation. The short worm-like pre-fibrils showed a faster adsorption kinetics to the oil/water interface to reduce the interfacial tension to a substantially lower level compared with the mature fibrils. The HIPEs stabilized by the worm-like pre-fibrils showed a wider range of oil phase volume fractions and protein fibril concentrations, which showed the characteristic connected polygon oil droplets network microstructure due to the squeezing of oil droplets. In comparison, the HIPEs stabilized by the mature mung bean protein fibrils were unstable, undergoing ostwald ripening with the appearance of big oil droplets shortly after the preparation. Consequently, significantly less free fatty acids were released from the HIPEs stabilized by the worm-like pre-fibrils compared with the mature ones in the in vitro stimulating digestion assay. Interestingly, compared with the HIPEs emulsified by the mature amyloid-like fibrils (HIPEs-M group), long-term oral administration of mice with the HIPEs stabilized by the worm-like pre-fibrils (HIPEs-W group) resulted in significantly lower body weight and substantially inhibited adipose expansion. The genes related to lipolysis were over-expressed and the expression of the lipogenesis genes were down-regulated in adipose tissue in HIPEs-W group compared with those in HIPEs-M group. Furthermore, fecal lipid content in HIPEs-W group was higher than that in HIPEs-M group; and the expression of genes related to lipid adsorption in intestine, such as FATP4, FABP-1, PPAR-α, MTTP-1 and CPT1A was down-regulated. Therefore, restriction of lipid digestion and absorption in intestine could serve as the mechanism for the inhibition of in vivo adipose expansion caused by the HIPEs stabilized by the worm-like fibrils compared with the mature fibrils.