Well, the life support consists machines and the energy to keep the machines running. The plants and animals are grown in the artificial enviroment of green houses and factory farms.
So life support and food are just machines and energy
It needs biomass, which is more than just machines and energy.
It needs knowledge on how to grow and use that biomass, which is more than just machines and energy.
Earth life doesn't like planet. You have to beat up the chemicals on planet in order to make it non-toxic to Earth life. However, Earth life biomass can be turned into soil that Earth plants like, which you can grow crops in, which you can feed to cows, which you can eat, then take the **** and process it into fertilizer.
This is a hard problem that takes lots of effort. And planet fights back -- sometimes unintentionally (random infection) and sometimes with mindworms.
...
Imagine if you land, and your city starts out with a basic biodome, a basic omnifactory, a small fission pile, and some basic lifesupport.
Stats: Production, Support, Energy, Population.
Fission Pile: +4 energy, 1 specialist nukee (+1 energy).
Omnifactory: +2 production, 1 specialist engeneer (+1 production -2 energy).
Basic Lifesupport: +2 support, 1 specialist biologist (+1 support -2 energy).
Planet itself is hard to use. You can send citizens outside, but such citizens require more life support resources. They can bring back raw materials (-1 support, +1 production, rocky terrain), use portable solar collectors to soak up energy (-1 support, +1 energy, high altitude), draw power off of mountain streams (-1 support, +1 energy, river).
Then you start researching.
As your tech gets better you can build improved base life support, better factories, improve your energy sources. Your ability to use the land surrounding your colony grows, and you gain the ability to build improvements on the land, and your specialists in-base get more efficient.
You find wheat seeds, which let you improve your diet -- no longer are your people eating just biosludge (with 75% of what your body needs to survive!) Your industiral base ramps up.
Eventually you gain the infrastructure to build a colony pod -- containing the basic infrastructure for people to survive on the planet. It is a big investment, but with it your eggs are not all in one basket anymore. And in any case, you found a rather good node of iron over in them there hills, and mining it from here is really expensive.
Fungus reprocessing, Van Neuman miners, Domed farms, self-assembling solar collectors...
Genetic technology advances. Exposure to planet biochemistry results in amazing discoveries about terran life -- things that nobody had ever realized where important. The first hybrid lifeforms are developed -- first, lichens, then trees capable of suriving the outside environment.
Eventually, food crops that humans can eat are produced, bringing about an agricultural revolution. No longer does it take intense productive and energy resources to grow crops in a simulated earth environment -- now, all you need is a few robotic harvesters and fertilizers.
And then ...
Call Health "Life Support", and if you are short on local food it stresses your life support systems.
