Food & Drink: Psychobiology and the mood foods: Carbohydrates make you happy; coffee boosts mental skills. Michael Bateman presents a psychologists guide to diet

DOCTOR Peter Rogers looks as if he's discovered the secret of eternal youth - imagine a youthful theyoung young Bamber Gascoigne at his most engaging. and bamber. Dr Rogers, With his tousled blond hair, open-necked shirt and jeans, Dr Rogers he actually looks closer to more like 20 than his real age, actual 40 years., like a youthful Bamber Gascoigne at his most engaging and bamber. If you are what you eat, he's a great advertisement for it.

Dr Rogers is head of the psychobiology unit at the Institute of Food Research, Reading, a place where people where they are acutely conscious of the effects of the food we eat. what you eat. And certainly Dr Rogers would agree that his trim frame owes somethingmuch to a careful, modern diet. Dr Rogers, Like Jack Sprat, he eats no fat or at least very little.

Of course, Eating less fat is, of course, very much in vogue line with the thinking of modern nutritionists, concerned primarily with whose the (their aim is being to reducereducing the risk of heart disease and other physical illnesses. But as a psychologist, Dr Rogers, as a psychologist, is finding there are more cerebral effects. A diet high in carbohydrates, for example, such as bread, potatoes, pasta and cereals, can have a positive effect on one's mood. a beneficial psychological effect by enhance mood, he says.

'In its purest form carbohydrate can affect the level of serotonin in the brain,' he says. 'It relieves a depressed mood and controls aggressiveness. It's also beneficial in cases of pre-menstrual tension, and in a state known as winter depression.'

Also, and this is of vital significance to would-be slimmers, He also reports that carbohydrates consumed without fat curb the appetite, a handy discovery of vital importance tofor would-be slimmers. , while On the other hand, Fat, however, on the other hand, including 'healthy' vegetable oils, as well as animal fats too) has the opposite effect. And, he says, the more fat you we eat, the more you we want, this is an effect many of us will have observed when most people will have probably noticed yourself when you take taking the cream to the strawberries or the hollandaise to the asparagus, opening a box of chocolates or turning your their our attention to the cheeseboard.

But while he is conscious of this nutritional distinction, Dr Rogers avoids the nutritionist's dichotomy may choose to label fat as bad and carbohydrate as good. but this is not necessarily the a stance approved of by a psychologists. like Dr Rogers. approves. He As a psychologist, he Dr Rogers is in a the position of to observing the consequences of such expert dietary advice and sees how it can trigger anxieties, food phobias, obsessions and certainly depression. He is by no means Dr Rogers is not the first to say there preach that there are no bad foods, only bad diets.

'We need to be relaxed about food to enjoy its benefits, not frightened,' he argues. 'not frightened. Someone once told me in a state of agitation that he had broken his diet; he was in a dejected state. He'd eaten one chocolate bar in the week.'

Dr Rogers works practices his psychobiology from an office wallpapered with diagrams of the neural order of the brain, press cuttings, cartoons and unlikely learned papers, such as notably 'How the nose cools the brain in the copulation of the rat' ('A joke this isn't my area.') A cutting declares that Tony Benn drinks 18 pints of tea a day. Good heavens. (No comment. 'He's a bit of a hero of mine.')

There is also a bald statement by one of his psychological guinea pigs: 'I don't drink decaffeinated coffee, since it gives me a headache.' Dr Rogers chuckles. 'Decaff doesn't give you a headache. It's the result of the withdrawal symptoms produced by coming off caffeine.' Coffee is one of his own areas of research. In contrast to other alarm-ridden scientific studies, Other scientific findings might create alarm about the physical effects of drinking too much coffee, but Dr Rogers's tests show that in moderateion amounts it coffee produces improves mental skills. 'I see coffee as a valuable tool in the workplace,' he says. He believes that people should decide for themselves how much to drink; How much you might people drink, he thinks, is up to them; you; he's not in the business of creating anxieties. So how much does he drink? One cup for breakfast and two or three cups during the morning at the office. Moderation in all things. 'Yes,' he laughs.

Along with his wife Andrea, a clinical psychologist, he is also a semi-vegetarian., along with his wife Andrea, a clinical psychologist. Could this be another clue to his wellbeing? A study published last month suggested suggested that this may be another clue to Dr Rogers' wellbeing, given reported that vegetarians appear to live longer. In Dr Rogers's case, it seems, they even appear to grow younger.

So what does he Dr Rogers eat? Generally, he advocates plenty of vegetables, fruit and carbohydrates is the his answer, with the emphasis especially on carbohydrates. His own research for example, has shown that a high-carbohydrate breakfast such as cereal leaves you more alert to start the day than a high-fat breakfast, such as a traditional fry-up. (sausages, bacon, eggs, fried bread). And there is the added bonus that, according to one line of research, carbohydrate acts as a mood regulator.

In any case, Dr Rogers finds from his own work that a diet high in carbohydrate tends to curb appetite while a diet high in fat has the opposite effect. 'It's actually difficult to over-eat on a high-carbohydrate diet. Carbohydrate gives you a feeling of fullness.'

Dr Rogers also says that, conversely, the more fat you eat, the more of it you want to eat. This is important news for dieters, especially as fats contain disproportionately more calories than carbodydrates. Another advantage of a

A high-carbohydrate diet is that italso provides a feeling of fullness, making it difficult to overeat. And carbohydrates contain far fewer calories than an equivalent amount of fat. Dr Rogers fishes out his scientific tables: 100g (3oz) of boiled potatoes (3oz) contain 75 calories. The same weight of vegetable oil of whatever variety (whether it's so-called healthy corn, sunflower or olive oil makes no difference) contains no fewer than 12 times as many calories (900) calories) and butter 10 times as many (740). calories). Despite this, he However, Dr Rogers refuses to make a moral judgement on fat intake. , however. That makes it things harder not easier, for dieters, he says.

'In an experiment with a group of dieters and non-dieters, both groups were given two ice-creams to eat. They were then led to a table piled with food and invited to eat as much as they wanted. The non-ate very little compared with the dieters. The dieters had this feeling about ice-cream, that it was 'bad', so once they had given in to it they let their barriers down. so They let themselves go completely, saying that they would get back on their diets the next day.'

Despite his efforts, to refrain from making judgements about people's food choices, Dr Rogers has found himself falling into traditional patterns of valuing food at home with his Though he tries not to be judgemental about what constitutes good and bad food, Dr Rogers We should try to avoid labelling foods as 'bad', he says, though he was amused to catch himself out at home with his children, 9-year-old Daniel, aged 9, and 5-year-old Nicholas, 5. 'I was telling them: 'Eat up your broccoli or you won't get any ice-cream.' This is a mistake, because you are reinforcing the child's value judgement: broccoli nasty, and ice-cream delicious.'

Psychobiology's time, as a food science, may have come. sounds like a fun food science whose time has come. Never before have our attitudes to food been so much in question, for wWe are clearly a society with serious hang-ups about food, and Dr Rogers is determined to challenge the basis of these problems. 'We value thinness in our society because to be thin and healthy is difficult,' he points outsays. 'It's also a sign of wealth if you can find time to go to health farms and do aerobics, or buy expensive slimming foods. But it's not a very relaxed way of life.'

He prioritises a relaxed attitude with his own and his family's diet, which Dr Rogers has a pretty relaxed way of eating, though it might seem a little ascetic until you get used to it. He starts the day with a bowl of cereal and has no more than a sandwich for lunch. For family supper they the family shares spaghetti with sauce (which he makes), or cauliflower cheese (which his wife makes) or an Indian take-away with rice if they have had no time to cook.

THE PSYCHOBIOLOGICAL DIET

Here is Dr Rogers's very relaxed and inexpensive guide to healthy eating. the pyscho-biological diet.

CARBOHYDRATES (potatoes, bread, pasta, rice, cereals). Active mood-improvers and , the perfect slimming aids when eaten without accompanying fats. And Remember, chips and crisps soak up fat.

CAKES, BISCUITS, CHOCOLATES, ICE-CREAMS Fine in their place, but consider their level of fat content. in them. It's the high level of cream or fat in an ice-cream that makes it so moreish. This applies to chocolate, too.

SUGAR Not a villain. Ripe fruits contain fructose, or and there's nothing wrong with stewed fruit with sugar. Don't let sugar dominate your thinking. It would be impossible to become overweight if you ate nothing but sugar. But add an equal weight of butter or cream, and you're multiplying the calorific value by 10.

FRUIT AND VEGETABLES Eat these abundantly for their nutritional value.

BUTTER, CREAM, ANIMAL FATS (dripping, lard etc). These saturated fats are those the ones which you should gradually be cut to a minimum. But don't be frightened of them.

MARGARINE, OILS Use in smaller amounts. Don't be rigid. Use a variety of fats and oils to get the the widest benefit from the different nutrients in them, rather than sticking to one type only.

CHEESE Consider how delicious the high-fat cheeses are. Enjoy in small quantities, but it may require an certain effort of concentration to avoid casually not to casually over-indulging.

BEEF, LAMB, PORK Good proteins, but go steady on the fattier varieties; sausages, pates and processed meats contain a lot. Dr Rogers' says Experiments suggest that most of us have a steady, balanced consumption of protein-rich foods which neither affect neither our health or our general wellbeing.

FISH Excellent source of protein, and 'oily' fish are especially beneficial mackerel, herring, sardines and, to a lesser extent, salmon.

TEA, COFFEE A cup of coffee has twice as much caffeine as a cup of tea. As a means of making you alert, a cup or two is fine. How much you drink after that is up to you. a matter of your own judgement.