Depending on which article you read in the press ‘Calorie count guidance may rise by a cheeseburger’ or ‘two bags of ready salted crisps’. Personally I would see it as 4 bananas, 8 apples, or 16 satsumas, but they seem less headline grabbing.

The headlines are based on a draft report prepared for consideration by the Scientific Advisory Committee on Nutrition (SACN). Current daily calorie recommendations are based on the ‘Estimated Average Requirement’ (EAR) published in 1991, but following a new method of calculating how much energy we use the SACN report suggests that even for inactive people this has been under estimated. The new findings imply that the current recommended daily intake of 2000 calories for women and 2500 for men could be increased by up to 16% so an extra 320 for women and 400 for men.

Whilst the report does acknowledge that the previous calculated EAR was incorrect, the authors do not suggest that everyone should be told they can eat more. In fact they suggest that education of people regarding calorie intake is necessary.

The report highlights that according to the National Diet and Nutrition Survey (NDNS) the amount of food people admit to eating is consistently below the previous daily calorie guidelines. However the NDNS and other surveys of the UK population show the number people classified as overweight or obese is increasing.  This can probably be explained by a combination of excess eating and inactivity.

The SACN report actually states ‘The high prevalence of overweight and obesity in the UK population shows that, for the majority of people, energy intakes are in excess of energy requirements. It is important that the proposed Estimated Average Requirement values are not used to signal or encourage an increase in energy intake of the population as a whole: this would increase the prevalence and magnitude of overweight and obesity in the absence of a corresponding increase in energy expenditure’.

We are already aware that the energy requirements for an individual depend on a number of factors including age, gender, body size and composition, pregnancy, and physical activity. A petite, 70 year old sedentary woman is not going to need as much energy as a tall 35 year old mother constantly running around with her small children.

So unfortunately this research is only acknowledging there is a more accurate method for calculating energy needs and does not mean we are all given a green light to eat more. We probably underestimate just how much we eat already, so we should instead increase our energy expenditure to follow the recommended 30minutes of moderate intensity exercise 5 times a week, and ignore the newspaper headlines.

There are scientific trials that have shown low carb-high protein diets provides more weight loss than high carb-low fat diets, but equally there are a number of studies that don’t show that effect. One study has shown that a low fat diet is better than a moderate fat diet, whilst others have shown that a moderate fat, Mediterranean style diet is superior to a low fat diet.

Whatever the diet, there is short term research out there to both support and disprove it. Now research published in the New England Journal of Medicine has examined the advantages of high fat, protein or carbohydrate diets over 2 years. Unlike other diet studies this one had a large number of participants (811), involved a high number of men (40%), and had good adherence to the diet by the participants (80% completed the 2 years study compared to normal diet studies where 40% drop out).

The participants were aged 30-70 years old with a BMI of 25-40. They were randomly assigned to one of four diets, with the percentage of energy from each food source being:

• Diet 1: 20% Fat; 15% Protein; 65% Carbohydrate
• Diet 2: 20% Fat; 25% Protein; 55% Carbohydrate
• Diet 3: 40% Fat; 15% Protein; 45% Carbohydrate
• Diet 4: 40% Fat; 25% Protein; 35% Carbohydrate

Each person was given a diet with a deficit of 750 calories a day as calculated from their resting energy expenditure and activity levels. Also 90 minutes of moderate exercise a week was prescribed.

Other goals of the diets were they should have

• 8% or less saturated fat,
• at least 20% fibre,
• 150mg or less of cholesterol per 1000kcal,
• carbohydrate foods with low glycemic index.

Typically weight loss is greatest 6-12months after starting a diet followed by a subsequent steady regain of weight. In this study at 6 months participants in each diet had lost an average of 6kg (7% body weight). The participants in each diet reported a reduction in calories of around 400kcal, although a mean weight loss of 6.5kg at 6 months corresponds to a reduced daily intake of approx 225kcal.

Even the study’s title is misleading ‘Calorific restriction delays disease onset and mortality in Rhesus monkeys’ as the authors conclude that overall when reducing calories in the diet mortality is in the predicted direction but not statistically significant.

The theory behind the study is valid. Since the first studies of caloric restriction in rodents in the 1930′s, scientists have been intrigued by evidence that reducing calories can effectively extend lifespan.

This study involved a colony of 30 female and 46 male monkeys over a 20 year period, who were introduced to the study when they were adults (7-14yrs old). Rhesus macaques have an average life span in captivity of 27 years which can reach up to 40 years old.

Initially the animals were allowed to eat freely from a low fat diet containing 15% protein and 10% fat. For 3-6months the baseline daily food intake was collected for each animal, with half the monkeys allowed to continue eating what they liked as a control for the calorie restricted (CR) subjects who had their diet intake reduced by 30%.

Of the original 76 animals, 37% (14 out of 38) of control animals died of age related deaths compared to 13% (5/38) of the calorie restricted animals, suggesting that free eating animals had 3 times the rate of death from age related causes compared to animals who were calorie restricted.

Seven control and nine calorie restricted animals died from what the scientists called non age related causes, with the effect of CR on overall mortality in the predicted direction but not statistically significant (p=0.16). These non-age related causes included complications of anaesthesia, gastric bloat and endometriosis. The problem with scientific studies is that you can’t just choose which results you want to include. If you are testing a drug to treat cancer but your subjects die from a heart attack you can’t just ignore those results from the study, you have to include all subjects you intended to treat no matter how or why they left the study. The deaths in this trial could be due to adverse reactions to the reduced diet, so shouldn’t be dismissed.

In addition, the study never mentions how many calories the monkeys ate and how it equates to a human diet. The control group didn’t eat a recommended daily amount for monkeys but were instead allowed to eat freely. How many calories would humans eat if they were allowed to eat freely and had no knowledge of the risks of over eating? Without knowing the recommended calorie intake for women, I’m not sure that I would restrict myself to 2000 calories a day, and looking around the street there are quite a few people who don’t restrict their diet. So it wouldn’t take much stretching of the imagination to think that a given a free choice a monkey could happily eat as much as the equivalent of 2600 calories. Maybe the study is actually comparing over eaters with those eating a healthy amount.

There are benefits that can be concluded from the study with the incidence of cancerous tumours and cardiovascular disease in animals on a restricted diet less than half that seen in animals allowed to eat freely. Also while diabetes was common in monkeys that can eat all they want, it wasn’t observed in any animal on a restricted diet. There are clearly benefits from the restricted calorie diet but whether it can be claimed it delays mortality may be stretching the study’s findings to date. What can be concluded is that before you believe all you read in the press, no matter how prestigious the publication, you may wish to read the scientific paper yourself.

Swimming works the whole body including arms, legs, back, stomach, bum and shoulders without straining your joints and muscles. But aside from it being an essential survival skill and a form of exercise in its own right, being able to swim allows you to participate in many more exciting activities. Waterskiing, white water rafting, scuba diving, windsurfing, canoeing, sailing and aqua aerobics are just some of the sports available to you once you can swim.

Over the last few weeks I’ve been swimming about 3 times a week, yet in the last 2 weeks I have lost 1 pound in weight. I have although, lost half an inch from round my waist and hips so I think swimming has been helping me to tone up. Swimming burns around 3 calories a mile (1600m) per pound of body weight, so if at 130lbs I swim 1000m I work off around 244 calories. Not the highest calorie burning activity. After swimming I often feel hungry after I have finished and I have to be careful that I don’t over compensate for the energy I have just used up by eating too much. This is because after swimming your body temperature is maintained and your metabolism stabilised unlike outdoor sports such as running which increases your body temperature, reducing the immediate desire to eat, whilst increasing your metabolism for up to 18 hours.

The buoyancy of water reduces your body weight by 90%, so whilst swimming is not the best exercise for weight loss or building muscle, it is a great activity to recover from injury as muscles are supported by the water. If you participate in other sporting activities, swimming is great as a form of cross training to regular work outs or help as a cool down moving blood through body to help it recover. Swimming should be combined with other training as it does not prevent osteoporosis because it is not weight bearing.

If you never learnt to swim as a child, or you need more water confidence there are many classes an swimming sessions open to adults. At the pool at I teach at we have timid adult sessions, where you can borrow floats and practise on your own with instructors on the side to offer advice if you require it. Most people swim widths without the fear of swimming in the way of the sprinters who normally swim lengths in adult only sessions. For adults who have never swum before adult beginner classes are great, often with an instructor in the water with you. In the classes I teach there is a great support and friendship developing between the other adult swimmers.

Body fat floats better than muscle and bones, which are dense don’t float well, so women, older people and those who are not very muscular often have more fat and may float more easily. Don’t forget that the density of water is important so floating in the sea which contains salt is easier than in a swimming pool.

Here are the benefits of the 4 main strokes:

Breast Stroke-This is the stroke that burns up the least calories but it is a great stroke to train the heart and lungs. Breast stroke works the chest muscles, whilst training the inner thigh, triceps, hamstrings and shoulder. However, using good technique is important as swimming breast stroke with your head above water is bad for your neck and back.

Back Crawl-Burns more calories than breast stroke and is great for toning you abdominals, bum, legs, arms and shoulders. It’s also good for lengthening and stretching your body.

Front Crawl-This is the fastest stroke and a good calorie burner, tones your bum, abdominals and shoulders.

Butterfly-This is the hardest technical stroke, but burns more than double the calories of back crawl and breast stroke. Important to be able to swim other stokes before you attempt butterfly. You can also cause injuries if your technique is poor so get instruction. Once you can swim butterfly it’s great for developing upper body strength and flexibility, whist toning your chest, abdominals, triceps, and back.

For more information on swimming in your area contact your local leisure centre or British Swimming.