Unnecessary fats. Beef has more unnecessary fats than bird meat or fish. Bison is a great alternative.. but if you want to eat horrible bars of butter and tubs of lard go ahead. Check out John Meadows Mountain Dog diet as that may interest you. All organic non gmo grass raised and finished and raw milk too.
The reason behind what I said was an easy way to avoid most food allergies/disorder and to keep it simple. It strips away everything the body is used to and limits it to strictly fuel for that day with no excess storage. Throw in a calorie defecit and you still supply muscle building fuel but also go keto. Keep it simple, get active and see a difference.
Any change in diet or exercise will have a physiological change.
Do not take my word as I am not a trainer or nutrionist or competetive bodybuilder. Do your own research and draw your own conclusions, we are all grown adults and just share opinions.
http://www.anasci.org/vB/bodybuildi...es-fats-structures-uses-why-we-need-them.html