There seems to be trends in what you can and can't eat but you should avoid too much viamin A - found in liver and sweet potatoes. Raw eggs and soft cheeses such as Brie. Oh and rhubarb (was an old wives tale but based on truth) as it has an enzyme that stops the body absorbing calcium.
i have a friend who is german but lives in this country and who spent a lot of time in france... they have different advice in germany and france on stuff you have to avoid! she just picks and choses the best one at the time
Generally most foods are ok in moderation - for example I don't drink milk or have many dairy products so I eat nuts. I was concerned that too many nuts can cause nut allergies but was advised that nuts in moderation were fine. It's best to stick to pasturised cheese, and avoid raw eggs, pate and things like that. Your doctor or health visitor can advise you better so if you are concerned you should ask them.
Sadly, for this time of year, Mr Whippy (or other similar soft ice cream) is a no-no.
And you shouldn't have too much tuna because of high mercury- i think the recommendation is a max of one steak or two medium cans per week.
But please speak to your midwife who can give you a full list. Or look in your NHS pregnancy book.
plocket, nuts are only to be avoided if you or your partner has an allergy, hayfever or asthma. If neither of you suffer from these then nuts are fine.