A method of making a diamond body, the method comprising: forming a diamond feedstock including at least a first fraction of modified diamond particles and a second fraction of diamond particles, the modified diamond particles having a surface topography with numerous nanometer scale asperities/cavities, pits and spikes that provide that the modified diamond particles fracture preferentially relative to the diamond particles of the second fraction during HPHT processing of the diamond feedstock; forming an assembly, wherein the assembly includes a layer of the diamond feedstock arranged in a refractory container; and processing the assembly at elevated temperature and elevated pressure sufficient to sinter the diamond feedstock into the diamond body, the diamond body having a microstructure including second fraction diamond particles dispersed in a continuous matrix including the first fraction of modified diamond particles and a binder phase, wherein, in the diamond feedstock, modified diamond particles in the first fraction have a D50 value of particle sizes of 0.1 μm to 3.0 μm and diamond particles in the second fraction have a D50 value of particle sizes of 10.0 μm to 40.0 μm determined as described in the description; and wherein the modified diamond particles exhibit a surface roughness of 0.50 to 0.80 which is a measurement of a two-dimensional image that quantifies the extent or degree of the pits and spikes of the particle's edges or boundaries as described in the description and which is determined by the ratio of the convex perimeter divided by the perimeter; and wherein the modified diamond particles exhibit a sphericity of 0.2 to 0.5 as described in the description and which is determined from the enclosed area of a two dimensional image or object divided by the square of perimeter. forming a diamond feedstock including at least a first fraction of modified diamond particles and a second fraction of diamond particles, the modified diamond particles having a surface topography with numerous nanometer scale asperities/cavities, pits and spikes that provide that the modified diamond particles fracture preferentially relative to the diamond particles of the second fraction during HPHT processing of the diamond feedstock; forming an assembly, wherein the assembly includes a layer of the diamond feedstock arranged in a refractory container; and processing the assembly at elevated temperature and elevated pressure sufficient to sinter the diamond feedstock into the diamond body, the diamond body having a microstructure including second fraction diamond particles dispersed in a continuous matrix including the first fraction of modified diamond particles and a binder phase, wherein, in the diamond feedstock, modified diamond particles in the first fraction have a D50 value of particle sizes of 0.1 μm to 3.0 μm and diamond particles in the second fraction have a D50 value of particle sizes of 10.0 μm to 40.0 μm determined as described in the description; and wherein the modified diamond particles exhibit a surface roughness of 0.50 to 0.80 which is a measurement of a two-dimensional image that quantifies the extent or degree of the pits and spikes of the particle's edges or boundaries as described in the description and which is determined by the ratio of the convex perimeter divided by the perimeter; and wherein the modified diamond particles exhibit a sphericity of 0.2 to 0.5 as described in the description and which is determined from the enclosed area of a two dimensional image or object divided by the square of perimeter.