According to Drawdown, reducing food waste is the top individual action one can take to reduce one’s impact on climate change. Buffets tend to be quite wasteful and/or encourage serving older food a lot more than a la carte orders. There could be some exceptions, such as buffets in hotels where it’s included in the room rent and is a lot easier to plan for (the quantities) based on the number of guests and the guest demographics.

As a consumer, if you want value for money in a buffet, the best bets, IMO, are fresh foods and/or the ones that aren’t processed much. All the high sugar and high fat processed foods tend to be made with low quality ingredients while also being terrible for health. Also focus on enjoying the variety with smaller quantities of everything you’d like to eat rather than trying to eat a lot more than your usual appetite.