I don't think that diet alone plays any major role in developing or progressing Male Pattern Baldness. Its the genes ! While some guys without bald genes eat rubish unhealthy diets and have full set of brilliant hair.. others with bald genes and top notch healthy diets end up bald anyway.
But also that beeing said, some types of rare 'foods' and compunds I believe can slow down or to a degree even fight the process. Also these anti-DHT and anti-5-alpha reductase foods and ingredients aren't exactly part of regular diets !
Please google up anti-DHT or anti-5-alpha reductase foods.
Many chemical compounds in nature are able to inhibit 5α-reductase, such as those found in the Reishi mushroom Ganoderma lucidum. Ganoderic acid or organoderol B may be the active compounds.
Medium chain fatty acids such as those found in coconut and the kernel of many palm fruits have also been found to inhibit 5α-reductase.
Other herbs include:
Brassica rapa (pollen)
Piper nigrum (leaf extract)
Serenoa repens or saw palmetto (active substance possibly lauric acid)
Pinus sp. (resin, active substance abietic acid)
Spore of Lygodium japonicum
I myself currently use 480mg of beta sitosterol. Saw palmetto which is on this list is often said to be much much weaker than beta sitosterol. The point I believe is to find a few strongest natural inhibitors and stick to them for months to see if they work. Its the hard way, but its the same even with minox and propecia. The major benefit however would be avoiding drugs side effects, natural inhibitors if used in right dosages I believe are much less likely to leave significant or permanent side effects and damage. Cost too should be much lower rhan with generic drugs.