If you do a Houzz search for "sustainable kitchen design" you will get pages of articles that contain those words. Type in the first 3 words and choices will appear for in stories, in photos, etc. Click on the in stories selection.

Sustainable design in the kitchen to me means not "fixing" or replacing things that are not broken just because they are "dated". Buying things such as servingware, glasses and mugs, etc second hand when they need to be replaced. Regardless of trends (this means having mix and match). And eliminating waste as much as possible, ie leftovers get eaten for lunch the next day not thrown out. Inedible food scraps get fed to the chickens or dog.

It's that simple, but it's not a popular choice because it doesn't present the image that is important to many people.

Definitely a broad topic with a lot of areas of focus. The threshold of how much one can live with is really dependent on the client. I would say that often the things that would have the biggest impact are often the least popular.

For the kitchen, think about adhesives, sealants and paints in terms of indoor air quality / VOC levels / off gassing. Make a pitch for FSC certified wood where you can (sometimes the delta isn't that much more expensive) and vie for the formaldehyde-free variety for engineered products like plywood and MDF. Better yet, search for reclaimed products where you can--really depends on the area and what you have available within a reasonable distance. Lighting, tight envelope and heating/cooling are all big topics that relate to every room.

But more than anything, the sustainable thing is not to build space you won't use. The extra stuff looks good, but think about what you'll use everyday rather than what you'll use once or twice a year. If you have an eat-in kitchen plus an island with seats, do you need the formal dining room? The extra fridge is nice at the holidays, but worth the energy use for the rest of the year? The space you don't build often yields the most impressive results from a sustainability perspective.