The studies finding make great headlines, but I wouldn’t consider them typical of the British youth. Over 1000 school children aged 8-15 were questioned in an online survey, restricting the demographic of the study to those who have access to the computer and internet and also the time and inclination to fill in an online survey (which from my experience you have to be referred to by an adult who is signed up to an online survey company). Taking into account this selected group of respondents it’s not too surprising that 55% of the children said that they spent 60 minutes or more a day texting, talking on the phone or using instant messaging and social networking sites. Apparently in this selective group of children, one in three did less than an hour a week of physical activity, surprising considering compulsory sports lessons at school.

If the same survey was taken of the children who visit the park from my house the results may be very different. Large groups of children hang around from the end of school till dusk, kicking a football on the astro-turfed pitch, cycling round the surrounding paths or just running and chasing each other. Although I doubt if you asked this group if they did regular exercise they would think that they did. Also the secondary schools in my area are over a mile away and each day you see the constant stream of children walking to and from school. If brisk walking is classified as moderate exercise then most of these are getting at least 60 minutess exercise a day without even trying or being aware of it.

One statistic that was interesting is that 20% said they thought they did not need to exercise because they were not overweight. Most health advertising is about watching watch you eat and being active to reduce obesity. Those in a healthy weight range probably don’t think it applies to them, so it is good that this year’s campaign is to encourage the importance of physical activity for all through an Ultimate Dodgeball event.

I teach both private and school swimming lessons and yes there are some obese children and those who try to get out of the lesson, but at the junior school age group I would estimate only 10% of those I teach are overweight. I have noticed however, that increasingly religion is becoming an excuse, the girls can’t swim because the costumes clings to their body when it gets wet, they are weak from fasting or the pool water can’t touch their lips. Perhaps these excuses should be addressed by the relevant bodies so children are freely able to participate in exercise classes and learn valuable live saving skills though swimming, without restrictions through their religion.

The BHF’s Food4Thought is a valid campaign and to make it into the tabloids it needed its shock statistics about the downfall of modern Britain, for papers like the Daily Mail to publish and promote the scheme. But can we have too many surveys like this putting down today’s youth and will children pay attention to a campaign that is already so critical of them? Maybe to be more active children need more freedom and fewer restrictions and they will happily ride their bikes to their friends’ house, choose to go to the swimming pool after school, or kick about the football in the park, without seeing exercise as a chore.

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.

According to today’s report by the European Centre for Disease Prevention and Control there have been 136,432 worldwide reported cases of influenza A (H1N1) resulting in 765 deaths. To put things in perspective only 1 in 178 people, or 0.56% who contract swine flu globally have died from it. Whilst any death is unfortunate, in a given year there are normally 4,000 deaths in the UK and 36,000 deaths in the US attributed to influenza, so there isn’t any extra need to panic.

But if you are obese or overweight there may be some added incentive to lose some weight. During the current swine flu pandemic there have been some observational reports that obesity is a risk factor for complications of the H1N1 virus infection.

There appears to be a correlation between obesity rates in a given country and the percentage of people who die from the swine flu.

There haven’t been official studies into the number of flu victims who are obese, so it’s unknown whether the deaths from swine flu are primarily in obese patients. However, the Morbidity and Mortality Weekly reported the case of ten swine flu patients at a Michigan hospital who became so ill they were put on ventilators. Three of the patients ultimately died from the infection.  Nine of the ten were obese, and two of the three who died were severely obese with no underlying respiratory conditions.

Whilst obesity has not been identified before as a risk factor for flu in humans, researchers at the University of North Carolina have studied the death rate of obese mice when they are infected with the flu virus. For 22 weeks, 70 female mice were fed a normal diet and 70 a high fat/high sucrose diet with all animals then infected with the influenza virus.

Lean mice developed mild disease and only 4% died whereas obese mice got extremely sick and 40% died due to severely impaired immunity. Obese mice also produced lower amounts of anti-inflammatory agents and also took 6 days to produce them, twice as long as the lean mice. Although the study was in mice the researchers think that obesity inhibits the ability of the immune system to respond to influenza infection and suggest that obesity may lead to morbidity from viral infections.

It’s not known whether the mice results are reflected in humans and the excess fat itself makes obese people more vulnerable by inhibiting their immune response. Alternatively it could be that people with a high body mass index who become infected get sicker because of related conditions like heart disease and respiratory complications which are harder to treat and become fatal.

Whilst the science behind the observations has yet to be confirmed, it appears that obese people have yet another health incentive to lose weight.

There are two common body shapes that develop when fat accumulates, apple shapes appear when fat collects in the abdominal area, this is termed upper body obesity (UBO). The other body shape is pear, when fat resides on the hips, which is known as lower body obesity (LBO).

Researchers from the Netherlands have investigated if the way the body deals with consumed fatty acids is different in men with upper or lower body obesity.  Previously research has shown that the chain length of dietary fatty acids is important in affecting fat absorption, fat metabolism and fat transportation around the body.

Medium chain triglycerides (MCT) are a type of dietary fatty acids which passively diffuse to the portal system (a system of blood vessels), without requiring modification or bile salts for digestion. Rich sources of MCTs include coconut oil and palm kernel oils. Some studies have shown MCTs can help the process of excess calorie burning and weight loss although almost half of the calories in your diet would have to come from MCTs themselves. 

Polyunsaturated fatty acids (PUFA) compared to MCTs are longer fatty acids which are absorbed into lymphatic system.  PUFA can be found in grain products or sea food. Beneficial PUFA include Omega-3 fatty acids found in fish, which reduce the risk of heart attacks and Omega -6 found in sunflower oil which can reduce the risk of cardiovascular disease.  However, high consumption of Omega 6 may increase the developmental risk of breast cancer in postmenopausal women or prostate cancer in men.

It has been suggested that within the body PUFA is disposed to the periphery (organs, muscles or subcutaneous fat) and MCT disposed more centrally. As MCT are often rapidly broken down than stored, a diet rich in MCT has been advised to people suffering from obesity problems

In the study published in this month’s Genes and Nutrition journal, researchers profiled adipose tissue biopsies from mildly obese men to investigate the effect of body fat distribution on the physiological response to two dietary fat interventions. Subjects with a BMI of 27-35 participated in the research.  Men with Waist to Hip Ratio (WHR) <1 were considered LBO and WHR>1 as UBO. As part of the trial they consumed a spread containing predominately either PUFA (71% long-chain fatty acids) or MCT (65% medium- chain fatty acids). Each day the subjects consumed 60g of the spread for two weeks.

The results showed a negative regulation of the metabolic pathways (lipid, carbohydrate and amino acid metabolism) in upper body obesity subjects when they consumed MCT compared to a PUFA diet. Despite previous recommendations that a  MCT based diet improves obesity traits, the findings from this study suggests a MCT diet in apple shaped people may have an adverse effect with increased inflammation and decreased energy metabolism in adipose tissue.

Dr Marijana Radonjic the papers author, reports that as there are different physiological characteristics of upper and lower body obesity, fat distribution is an important parameter to consider when selecting a personalized dietary regime.