Yeap indeed. However, have in mind that vegetarians and vegans often go to the wrong approach (consuming plenty of highly processed oils as well as enormous amounts of seeds).

P.s: coconut oil, peanut oil, etc are often overused in the preparations of foods.

• Roberts, Rosebud O., Yonas E. Geda, James R. Cerhan, David S. Knopman, Ruth H. Cha, Teresa J.H. Christianson, V. Shane Pankratz, et al. “Vegetables, Unsaturated Fats, Moderate Alcohol Intake, and Mild Cognitive Impairment.” Dementia and Geriatric Cognitive Disorders, 2010. https://doi.org/10.1159/000305099.
• Biase, Simone Grigoletto De, Sabrina Francine Carrocha Fernandes, Reinaldo José Gianini, and João Luiz Garcia Duarte. “Vegetarian Diet and Cholesterol and Triglycerides Levels.” Arquivos Brasileiros de Cardiologia, 2007. https://doi.org/10.1590/S0066-782X2007000100006.

And when it comes to the ketogenic diet:

• Kalra, Sanjay, Rajiv Singla, Rahul Rosha, Munish Dhawan, Deepak Khandelwal, and Bharti Kalra. “The Ketogenic Diet.” US Endocrinology, 2018. https://doi.org/10.17925/USE.2018.14.2.62.

If you want to download scientific articles for free, use this tool:

• https://sci-hub.tw/

It's a little bit buggy but it works