The research found that adults with overweight who followed a low-fat vegan diet reduced the energy density of their food by about 30%. Participants were placed either in a low-fat vegan diet group or in a control group that continued its usual diet. In other words, people following the vegan diet were still eating roughly the same amount of food by weight. Compared with the control group, people eating the vegan diet reduced their energy intake by about 357 calories per day. Another point is that a vegan diet needs to be nutritionally well planned.