Reader: Over the past month I haven't been eating meat and I have found myself to be really tired and unmotivated with almost everything, but especially when it comes to getting my 'five-a-day'.

I know I need to be eating plenty of iron-rich foods, but I'm really struggling to eat much fruit (I'm eating vegetables within my meals). How can I increase my fruit intake and also my snack intake as I'm not eating nearly enough during the day as I don't feel hungry?

Catherine Matthews: It sounds as though you may be at risk of iron deficiency as you are feeling tired and lacking an appetite. You need to increase your intake of iron to prevent iron deficiency anaemia. It's harder to get enough iron if you don't eat meat, so you need to take care to eat plenty of foods that are rich in iron. Try to eat a good selection of the following:

• wholemeal bread and wholegrain breakfast cereals
• pulses such as lentils, kidney beans and chickpeas
• green vegetables such as watercress, spring greens, broccoli and okra
• eggs
• dried fruit such as prunes, apricots and figs
• nuts such as peanuts, almonds and brazils
• shellfish

Eating foods containing vitamin C helps us absorb iron from non-meat sources, so it's a good idea to have a glass of fruit juice with your toast or cereal in the morning. Try to avoid drinking tea with meals and for half an hour afterwards because this can reduce the amount of iron you absorb.

To increase your intake of fruit, make meals and servings containing fruit more interesting and tasty. Why don't you have fruit salads with a dollop of low-fat yoghurt, or stew fruit and add some raisins, sultanas or cinnamon for flavour. Also make smoothies; this is a great way of increasing the amount of fruit you are consuming.

Reader: How much protein should we be eating every day and what exactly constitutes a portion of protein? For example, is a quorn burger one portion? And do dairy products such as yoghurt and milk count as portions? I often worry that I'm not eating enough but I've read that it's very rare that people are deficient.

Catherine Matthews: You should aim to eat between 0.8 and 1 gram of protein per kg of bodyweight per day. Good protein foods include lean meat, fish, eggs, poultry and beans, while vegetarian alternatives include soy and quorn. Dairy products are also good sources of protein although they are slightly lower in protein than meat or fish and the vegetarian alternatives.

Most people have no problem meeting the RDA (recommended daily allowance) for protein as long as they are eating a healthy, balanced diet.

Reader: I have heard on various occasions that you should not eat fruit before you go to bed. Could you please tell me if this is true and if it is then why? I enjoy nothing more than a bowl of fruit salad with yoghurt before bed. Is it also true that you should not eat fruit with other food groups such as dairy?

Catherine Matthews: The timing of eating fruit really is an individual decision. Some people prefer not to eat it before going to bed because they find it can upset digestion as some fruits are quite acidic. However, there really is no conclusive reasoning for avoiding fruit as a night-time snack. In fact, personally I feel fruit is great to have before going to bed as it is nutritious, low in calories and will not fill you up too much.

Reader: I am very confused about coffee. Should one drink it or avoid it? Or, as with so many of these things, is it alright in moderation? Is real better than instant, and what about decaffeinated?

Catherine Matthews: It really is very difficult to give a definitive answer in relation to coffee. New evidence is constantly coming to light but, more often than not, the research conflicts with studies previously carried out.

We do know that caffeine found in both instant and 'real' coffee can have disturbing effects on a person if consumed in large amounts, such as causing imbalances to blood sugar levels and hormones. However, as long as you limit your intake to 3-4 cups per day you should not experience the side effects associated with caffeine intake.

Reader: Lots of regulars on the YCDIDS (You Can Do It Diet Support) board seem to think it's a bad idea to eat carbohydrates in the evening. What's your view on 'carb curfews' and what would you recommend as an evening meal when it's your main meal of the day?

Catherine Matthews: The timing of eating carbs really is not important and it is a complete myth that eating carbs after a certain time leads to weight gain. The main meal, whether in the afternoon or evening, should contain a balance of all the food groups, i.e. carbs, fat and protein.

Aim to have a wholegrain food such as wholemeal pasta or brown rice with veggies and a protein source such as eggs, lean meat, poultry or fish. Have a small, low-fat yoghurt with a piece of fruit after the meal if you are still hungry.

Reader: Just wondered if you could suggest any low GI between-meal snacks of about 100 kcal to fit in the with Rosemary Conley GI Jeans diet?

Catherine Matthews: Good low-calorie, low GI snacks include fruit salad, plain yoghurt, wholegrain crackers with peanut butter, hummus with vegetable dippers, mixed seeds and nuts (small amount), cottage cheese and a piece of fruit.

Reader: Is it normal to get days when you are particularly hungry? I find that normally I eat sensibly, mostly low GI, and am satisfied, but every so often I get a day when I am really, really hungry and all I want to do is eat, even though nothing - the amount of water I drink, the amount of exercise I do - has changed. Do you know why this would happen?

Catherine Matthews: It certainly is not unusual to have days when you are feeling very hungry. There may be a number of reasons for this such as hormonal changes occurring before or after your period, stress or leaving large gaps between meals. On these 'extra hungry days' you just need to increase your motivation and be a little more disciplined.

Snack on fruit and veg rather than calorie-laden snacks and aim to eat lots of small meals during the day. The trick to preventing hunger is to eat little and often. If you are hungry, eat a small amount of food and wait for a few minutes to allow your brain time to register satiety. Often a small amount of food will be enough to offset cravings and hunger.