When we sit down to write fiction, no matter what genre, we must consider two aspects of worldbuilding: food and how the climate affects what is served for our fictional meals.
Every fantasy world has a setting, and that environment has a climate. Certain climates limit the variety of foods available.
First, let’s look at real life. You can’t create a believable fantasy unless you have some idea of reality.
We had a normal June this year, with only one day rising into the 90s and the rest almost (but not quite) as they should be: overcast, rainy, and cool. Climate-wise, we Pacific Northwesterners usually have similar weather as those of you in Wales or England.
Last year in June 2021, we had an unprecedented heat wave that killed much of our locally produced crops. How did that heat wave affect crop production here in the Pacific Northwest?
Farms experienced serious losses, as the heat wave baked the fruits and berries or otherwise destroyed the crop and the drought conditions worsened.
10 million pounds of fruit a day were being harvested in the Pacific Northwest at the time the heat wave struck. Farmers in Eastern Washington, facing a loss of the cherry and blueberry crop, sent workers into orchards at night to avoid the heat in the day.
The British Columbia provincial fruit growers’ association estimated that 50 to 70 percent of the cherry crop was damaged, effectively “cooked” in the orchards.
Raspberry and blackberry farms in the Lower Mainland, Oregon and Washington also endured losses. In Whatcom County, Washington, which produces four-fifths of raspberries in the United States, estimates varied from quarter to half of the harvest; elsewhere, they went as high as 80-90%. Lettuce producers in the Okanagan Valley also reported crop losses, and so did those who grew Christmas trees and apples. 
This year, 2022, June had an overabundance of rain, but I didn’t complain because the memories of last year’s heat wave were still too strong. However, the excessive rain and lack of sunshine impacted our spring and early summer crops.
An article by Mai Hoang for Crosscut News (June 15, 2022) says:
This year, the cold and wet spring stunted the development of many cherries, leading to what looks to be the smallest crop of Northwest sweet cherries in nearly a decade. 
If I were writing a speculative fiction story set in Earth’s near future, I would look at current agricultural technology to see what is possible and to gauge future trends. After all, climate change is happening and must be accounted for, even in futuristic fiction.
We know from bitter experience that weather affects the food we produce and influences what is available in grocery stores. Abnormal heat waves across temperate states, category 4 hurricanes along the Atlantic seaboard and the Gulf of Mexico, and category 4 tornadoes down the center of the US and Canada, and even deep freezes in Texas and the deep south have been our lot in the last five years.
We humans must adapt our agriculture to withstand our increasingly unpredictable climate if we hope to survive. And, our fiction must reflect it, whether it is set in the current times or a not-too-distant future.
In real life, a new trend in agriculture is occurring. Farmers in Europe and Canada are increasingly turning to greenhouse agriculture, from small, owner-operated farms to industrial farms. Greenhouses in these countries reliably supply seasonal produce year-round, with far less need for chemical pesticides and highly efficient water use.
The Statistical Overview of the Canadian Greenhouse Vegetable Industry, 2019, tells us that the Canadian greenhouse vegetable sector is the largest and fastest-growing segment of Canadian horticulture. Greenhouse farming produces agricultural products in self-contained ‘controlled environments’ with systems supplying heat, water, and nutrients and often employing artificial lighting (in addition to sunlight) to nourish the plants. 
Wikipedia tells us: Greenhouses may be used to overcome shortcomings in the growing qualities of a piece of land, such as a short growing season or poor light levels, and they can thereby improve food production in marginal environments. Shade houses are used specifically to provide shade in hot, dry climates.
As they may enable certain crops to be grown throughout the year, greenhouses are increasingly important in the food supply of high-latitude countries. One of the largest complexes in the world is in Almería, Andalucía, Spain, where greenhouses cover almost 200 km2 (49,000 acres).
The Netherlands has some of the largest greenhouses in the world with around 4,000 greenhouse enterprises that operate over 9,000 hectares of greenhouses and employ some 150,000 workers. 
Once you have decided your historical era, terrain, and overall climate, research similar areas of the real world to see how weather affects their approach to agriculture and animal husbandry. Look into the past to discover ancient agricultural methods to see how low-tech cultures fed their large populations:
Wikipedia says this about Incan Agriculture: Farmers usually had many different, scattered plots of land on which they planted a variety of crops. If one or more crops failed, others might be productive. In many areas of the Andes, farmers, communities, and the Inca state constructed agricultural terraces to increase the amount of arable land. 
Are you writing a narrative set in our current or near-future world? Post-apocalyptic stories often feature food shortages, detailing how starvation leads to civil unrest, making life unsafe for those clinging to their homeland. Refugees are driven to seek better lands where they may not be welcomed. This, in turn, often leads to more civil unrest.
Historical fiction must also be true to the type of food available in that area and era. Many common foods we now consume anywhere in the world were only available in South America, or in Europe, or in Asia, or in Africa. It wasn’t until after the time of Columbus that the cultivation and propagation of many now-common foods began to travel all over the world.
Also, if your story is set in a particular era, how plentiful was food at that time? Famines occurring all across Europe and Asia over the last two-thousand years are well documented. Egyptian, Incan, and Mayan history is also fairly well documented so do the research.
Weather is a driving force in our real world. Rain, heat, storm, or drought—weather in its many forms destroys homes, destroys crops, and costs us billions of dollars annually.
How it affects our food supply is not just news for television. It is a reality our governments must consider if they hope to stave off civil unrest in the future. Subsidizing greenhouse agriculture could help resolve future food insecurity and make the best use of limited water resources.
We have witnessed monumental changes since the turn of the millennium. We know California teeters on the edge of disaster, that a water shortage threatens the lives of millions, as well as one of the largest agriculture industries in the US.
Food and water insecurity leads to volatile politics.
Sit and think about your world, about the climate and how it affects the society you are writing about. Let your mind wander with no apparent destination. You will be amazed at what a mind technically at rest can come up with when it’s allowed to roam.
How well will your fiction hold up in two decades? Will you have the foresight of those who founded the genre of speculative fiction? Will you write another Nineteen Eighty-Four or Fahrenheit 451? How much will you get right?
Build detail into your world in a separate document from your manuscript. Blend what you know about the real world into it. Write out all the details that will never make it into your story.
When you can see your written world as clearly as that which exists outside your windows, that vision will come across in your writing. The food they so casually serve, a meal that involves less than a paragraph, will be a part of the scenery. It won’t jar a knowledgeable reader out of the narrative.
Credits and Attributions:
 Wikipedia contributors. 2021 Western North America heat wave [Internet]. Wikipedia, The Free Encyclopedia; 2022 Jul 1, 03:55 UTC [cited 2022 Jul 2]. Available from: https://en.wikipedia.org/w/index.php?title=2021_Western_North_America_heat_wave&oldid=1095905315. (Accessed July 2, 2022.)
 Quote: NW cherry crop this year may be the smallest in nearly a decade, Mai Hoang June 15, 2022, ©2022 Cascade Public Media. All Rights Reserved. https://crosscut.com/news/2022/06/nw-cherry-crop-year-may-be-smallest-nearly-decade (accessed July 2, 2022). Fair Use.
 Statistical Overview of the Canadian Greenhouse Vegetable Industry, 2019, Statistical Overview of the Canadian Greenhouse Vegetable Industry, 2019 – agriculture.canada.ca updated, 2020-12-30. (Accessed July 2, 2022).
 Wikipedia contributors, “Greenhouse,” Wikipedia, The Free Encyclopedia, https://en.wikipedia.org/w/index.php?title=Greenhouse&oldid=1095255341 (accessed July 2, 2022).
 Wikipedia contributors, “Incan agriculture,” Wikipedia, The Free Encyclopedia, https://en.wikipedia.org/w/index.php?title=Incan_agriculture&oldid=1095070716 (accessed July 2, 2022).