Not eating meat or dairy wasn't an issue as I was used to that, but since this is a low-fat diet, I cut way back on avocados, nuts, seeds, and oils. I was so used to grabbing handfuls of raw almonds, adding sunflower or hemp seeds to my salad, and smashing avocado on my toast.
I had to stop roasting and sautéing my veggies and tofu in oil, so I baked and steamed instead. An HCLF vegan diet emphasises whole foods, so I also cut out flour, sugar, and processed foods like protein powder, salad dressing, hummus, and vegan ice cream.