Last week I gave you dietary tips for conception and this week I'm back with advice for pregnancy... I'm not presuming you have all got cracking that quickly, but I'm just on a roll! For the non-pregnant out there, rest assured that next week I'll be kicking off another round of "try this, not that''. However, as every other woman I see is pregnant at the moment, I'm hoping this will come in handy.

After all, there seems to be something in the water. Pregnant women are everywhere – and not just in Daisy and Mac either. Yesterday, on my way back from lunch I saw seven pregnant women all in a row – in fact, join me in a little social experiment and see how many you can spot when you are next out and about in town. We may genuinely be going through a baby epidemic but perhaps I just notice more these days. Or maybe it's because we are now so out and proud (and rightly so) with our bumps, that pregnancy is just more obvious.

It's funny, some people love a pregnant bump and other people are a little alarmed. My Uncle Richard all but resorted to wearing a rainsuit around me in my last few weeks. I looked ready to pop and he was concerned my waters were going to break at any given moment. Other people couldn't resist coming up and rubbing my belly – which was fine by me. A friend of mine, however, ended up buying a T-shirt that read "touch my bump and I'll slap your face" – point taken.

Finding something to wear was, in the end, the easiest part of being pregnant. It just so happened that everything in the shops was loose and empire line. Also, I discovered www.isabellaoliver.com and developed a bit of an addiction.

Oddly, the hardest part was figuring out what to eat! Now obviously I should have known this, but between standard pregnancy restrictions, emerging research on the mercury content of fish, a debate over whether or not pregnant women should eat nuts AND a dairy allergy, things were complicated. Oh and to make life even harder, all I wanted to eat for the first three months was ginger snaps.

So, for those of you out there who have little ones on board and are a bit confused about what you should be eating, here's what I discovered:

Eating for two

Eating "for two" is sadly a bit of a myth so before you sit down with a pint of ice cream and a Mars Bar, note that you only really need an additional 100 calories per day in the first trimester and 300 in the second and third trimesters. Further, these extra calories should be quality, nutrient-dense calories, rather than the "empty" (nutrient poor) calories that come from junk food.

It is inevitable that you will put on weight during pregnancy, but try and keep this within healthy guidelines. If your body mass index (BMI) is under 20, you should gain approximately 28-40 lbs, if your BMI is 20-25 you should gain 25-35 lbs and if your BMI is 26 or above, then you should gain 15-25 lbs.

Of course everyone is different and you should certainly never "diet" during pregnancy, but bear in mind that too much weight gain can lead to problems such as high blood pressure and gestational diabetes.

Fish

Elevated levels of mercury in fish are a concern as mercury can harm the developing brain. In 2003, the Atlantis Project at the then Bermuda Biological Station for Research, did identify elevated mercury levels in human foetal cord blood and in some local fish species.

In contrast, most fish are also rich in "good" fat. The good fat in fish is otherwise known as Omega 3 – a vital nutrient for the rapidly developing brain of a baby. However, this doesn't mean that you should ignore the mercury content of certain fish, and it's certainly advisable to monitor your intake.

As the fish at the top of the food chain tend to have the highest concentrations of mercury, pregnant women should try and stay clear of shark, tuna and wahoo.

Also, it's worth noting that fresh/canned tuna, cod, sole, marlin and swordfish have been shown as having a relatively low Omega 3 content and relatively high mercury content, so they are best kept to a minimum.

The guidelines for pregnant women from the Environmental Working Group (www.ewg.org) are as follows:

Avoid: Shark, Swordfish, King Mackerel, Tilefish, Tuna steaks, Canned tuna, Sea bass, Gulf Coast Oysters, Marlin, Halibut, Pike, Walleye, White croaker, Largemouth bass

One serving per month max: Mahi Mahi, Blue Mussel, Eastern Oyster, Cod, Pollock, Great Lakes Salmon, Gulf Coast Blue Crab, Catfish, Lake Whitefish

2-3 servings a week: Mid-Atlantic Blue Crab, Croaker, Fish Sticks, Flounder, Haddock, Trout, Salmon (preferably wild), Shrimp

Nuts

Currently, in the US, the Committee on the Toxicity of Chemicals in Food, Consumer Products and the Environment states that women who have a family history of allergic disease (or who have a partner who does) are recommended to avoid peanuts and peanut products while pregnant and breastfeeding. The aim is to reduce the risk of babies developing a peanut allergy. Note that "allergic diseases" include asthma, eczema, hay fever and food allergies.

Whilst the committee suggests that without a family history of allergic disease, these recommendations do not apply, some paediatricians and obstetricians in Bermuda are advising all pregnant women to avoid peanuts and other tree nuts in order to combat nut allergy in children. However, this is a controversial area as unroasted/unsalted nuts can be a valuable source of protein and good fats for pregnant mothers, especially those who are vegetarian or vegan. I would advise all pregnant women to discuss this with their doctors before making a decision.

Protein

Carbohydrates, fats and protein are all important during pregnancy, but many pregnant women overlook an adequate protein intake in favour of carbohydrates. However, protein is required for the physical growth and cellular development of your baby, so it's really important to get enough.

Aim to eat one source of quality protein (lean red meat, poultry, fish, tofu, nuts [with restrictions above], eggs, dairy, brown rice mixed with beans or lentils) with every meal or snack. For sensible guidelines on protein, carbohydrate and fat servings during pregnancy, visit www.marchofdimes.com.

Folic Acid

Folic Acid is crucial for helping to prevent neural tube defects in your developing baby and for supporting your increased blood volume. All pregnant women should be taking a daily prenatal supplement that contains 400ug of folic acid. It's useful to eat folic acid rich foods too: these include fruit and vegetables (especially oranges, bananas, green leafy vegetables), beans, pulses, milk, yoghurt and yeast/malt extracts such as Marmite.

Calcium

Whilst pregnant, your baby will get all the calcium they need from you. It is far more likely that you will end up calcium-depleted rather than your baby! In order to protect your bone density, have a look at the calcium content of foods you eat regularly and check you are getting 1,200mg daily.

If not, either eat more calcium rich foods (green veg, almonds, hummus, dairy, enriched soya products, wholegrains and pulses) or consider supplementation.

Note that if supplementing, calcium citrate is the most easily absorbed form of calcium, and that calcium requires adequate vitamin D and magnesium to be absorbed - the staff at Down to Earth and Rock On should be able to point you in the right direction.

Iron

Iron is important for blood supply to the placenta and baby. Iron-rich foods include lean red meat, fish, poultry, dried fruit, wholegrain bread, chick peas and lentils.

Caffeine

The advice regarding caffeine intake is mixed. The US Department of Health suggests that pregnant women avoid caffeine completely, March of Dimes recommends less than 200mg daily and Baby Centre suggests a limit of 300mg. To make sense of this, note that one strongly brewed 8oz cup of coffee contains 300mg of caffeine.

As some research has linked caffeine intake to heartburn in pregnancy, pre-term labour and low birth weight, it's worth being very careful.

Coffee, chocolate, cola and energy drinks all contain caffeine. Even decaffeinated coffee contains some caffeine, just less.

Alcohol

This is another controversial area. The US National Institute for Health & Clinical Excellence recommends that no alcohol be consumed during pregnancy. This is of course alarming for those of us that weren't exactly planning our pregnancies! However, while the effects of a small amount of alcohol are largely unknown, bear in mind that alcohol does cross the placenta to your baby. At its worst, frequent binge drinking can result in brain damage, facial abnormalities and growth deficiency. A high alcohol intake has also been linked to miscarriage, premature birth and still birth.

Further, heavy alcohol consumption has been linked to hyperactivity and developmental difficulties in children.

Water

Drinking lots of water is important for your baby, but also for helping you feel energised and preventing constipation. It's also a good way to avoid caffeine and sugary drinks. Remember that many sugary drinks (such as Tropicana Twister, Sunkist and even Vitamin Water etc) contain up to 21 teaspoons of sugar!

A high sugar intake is a fast route to gestational diabetes and contributes to weight gain, so avoid sugary drinks at all costs!

Cravings

Are cravings your body's way of telling you what your baby needs? Possibly. I know that every time I ate spinach I had a sudden and urgent need for orange juice – interesting, as vitamin C helps the folic acid from green leaves be absorbed into the body. However, if you have a constant craving for sugary junk, it may be that your blood sugar has fallen too low and what you are feeling is the need for a quick "pick me up". The answer here isn't to keep feeding yourself sugar, but instead to try and have well rounded meals containing protein and complex carbs. However, if morning sickness prevents you from eating optimally, just try and choose low sugar options and eat little and often.

Standard restrictions

You probably know all these, but pregnant women are advised to avoid the following: raw or rare meat and fish (including sushi), deli meats, hot dogs, sprouted seeds and beans (e.g. alfalfa), soft unpasteurised cheeses, raw eggs and refrigerated smoked seafood (e.g. smoked salmon.) The reason is that these foods put all people at a higher risk for either listeria or salmonella. The problem with being pregnant is that if you get either of these, the implications are far more serious than for someone who isn't pregnant. Listeria and Salmonella have both been linked to premature birth, miscarriage and still birth.

What does that leave?

So, after all that, what does it leave you? In pregnancy, the very best diet is rich in quality protein, wholegrains, fruit, vegetables, salads and pulses. Try eggs/wholegrain toast, wholegrain cereal or yoghurt and berries at breakfast.

Have a big chicken and avocado salad at lunch time and lean beef, green veggies and sweet potatoes for dinner.

Snack on fruit, nuts (except peanuts) if you have no history of allergic disease in your family and if your OBGYN approves, hummus and crudities.

Of course some days, this may all go to pot and you may end up eating three ice creams and a burger. If you do, don't beat yourself up, just aim for the best the majority of the time and your baby will thank you for it!

The advice given in this article is not intended to replace medical advice, but to complement it. Always consult your GP if you have any health concerns. Catherine Burns is a fully qualified Nutritional Therapist. Contact her at clinicalnutrition@gmail.com.