Cook with oil if you want to increase your chances of ms relapses and disability. Vegetables are fine roasted without any added oil at all. Just add FSO after cooking yum yum.
Neurologists count relapses in decade increments, so beware comfort stories re: 'go with what works with your particular body', as it can be too late after you realise it damaged your health. Beware the slippery slope of wishful magical thinking. OMS is based on rigorous science including population studies across time. OMS is not guidelines for you to fiddle with and then recommend your personal variations to others (esp people who are still learning the program). OMS is a lifestyle program with clear guidelines to follow if you choose to increase your likelihood of staying as healthy as possible. Your individual health is too precious to gamble on by adding oil to your cooking and waiting up to 5-10 years to gauge the incremental impact on your health.
Under the OMS program, you may occasionally choose to add a very small amount of good quality EVOO to your cooking that IMPORTANTLY also has water in it to keep oil below 100oCelcius. Water dries out very rapidly while baking and you're probably not wanting to add water to your baked potatoes so just add nothing at all. Also, the oil would be floating on top of the water and exposed to hot air of oven temp. Don't bake oil above 100oC unless you choose to just play pretend that you're following OMS. Baking at low temps doesn't give you a crisp finish so the slight change in taste isn't really worth the bother of keeping enough water but not too much water in with the oil. You also need to watch out that small amounts of added oil for your taste can gradually increase to larger amounts. Note that even the original Mediterranean diet would often add oil after cooking. Current cooking in that region has gotten unhealthier and so their health has deteroriated too so don't look to their recent cooking styles
Aim for zero saturated fat (ie keep to 5 grams for optimal health, and that leaves you some allowance for inadvertently eating more oil or damaged oils when you do eat out). Avoid poor quality, oxidised oils. ALL cooking oxidises oils, it is not an exact science but the longer the cooking (ie baking) and the hotter the temp (stove top) and the older or more light and heat exposed (incl storage conditions) the oil, the greater the oxidisation, and its effect on your health is accumulative over the longer term. There are chemical certifiers of batches of EVOO in some countries (see if they're available on the EVOO you buy, incl the date of pressing on the label eg Cobram estate) as studies show that Italy exports a lot of inferior ie already oxidised EVOO. Oxidisation is not the same as going rancid so you often can't tell yourself
There is still loads to enjoy. I'm a creative foodie with a sensitive sense of smell and taste. Oil added on food afterwards is delicious- I can't believe it took me until OMS to discover the delights of FSO. If you want to eat EVOO (keep it to small quantities) then become a connoisseur of which EVOO you buy and you can enjoy the flavour better if you don't cook it and you only need small occasional amounts.
One cooking option is toss your chopped pototoes or sweet potatoes in spices eg a curry blend, or chaat masala before dry roasting. If you toss your cut potatoes around very viciously(!) in closed container or bag until the sides get roughed up a lot, that change in texture gives you an interesting effect when dry roasted ie without oil that approximates the crispness of oil roasting. Or just steam baby potatoes and add lots of salt on at end, then service with your own spanish dipping sauces salsa rojo (red capsicums, herbs, sherry vinegar) and salsa verde (google recipes). You can make a delicious deconstructed ratatouille by putting red capsicum (peppers), eggplant, tomatoes, red onion, mushrooms (release liquid too) and herbs in large baking dish covered with foil and a small bit of water to stop it burning before the vegies start to release their liquid. great with rice/buckwheat/quinoa/whichever and sprinkle on raw nuts and fresh herbs and your own dressing. Or slow roast an entire pumpkin whole until soft, then serve sliced with skin on, alongside bread/rice/buckwheat/quinoa/whichever and sprinkle on raw nuts and fresh herbs and your own dressing again. Make a sofrito as a base for your sauces and stews etc by simply water frying onion etc on a low temp, then the onion starts to release an oily slipperyness. Mushrooms can help that too. All of these dishes I just mentioned taste best by far with FSO or occasionally EVOO on top after cooking. Good for risotto too. If your food is still hot, you can put your serve of FSO in a tiny dish or cup on the side and put a little on as you eat like a delicate condiment so it doesn't heat and lose its benefit for you. happy eating!