According to the House of Commons Select Committee on Health: “At its simplest level, obesity is caused when people overeat in relation to their energy needs.”(6)
Overeating is, of course, a relative term and simply means taking in more energy than you use up through physical activity. It follows that different people have different energy needs. An energy intake of 3,000
kcal a day might not be enough for an athlete in training but would be far too much for a petite office worker.
If you’re a man aged 19 to 50, your average energy need is about 2,550 kcal per day. A woman in the same age range needs only about 1,940 kcal.(57) Regularly taking in more calories than this – whether consciously or because of subtle changes in food over the past few decades – leads to storing body fat
and to being overweight or obese.
Changes in Diet
Obesity in the UK grew slowly from about 1920 but accelerated after the Second World War. Diet isn’t the only cause but it plays a key part, particularly the changes that have taken place in the past few decades.
Our diet today is no longer rich in complex carbohydrates such as grains, wholemeal bread, potatoes, vegetables and pulses, with a reasonably low fat content. It includes much more meat, cheese, butter and other rich milk products and more alcohol.(58) And the fat content has gone up considerably.
Fat is packed with energy, with over twice the calories of protein or carbohydrate (nine kcal per gram against four kcal per gram). It’s not only calorie dense but, along with alcohol, one of the least filling of nutrients(59) (see Densely Satisfying). In order to feel full, you have to eat much more of it than starchy foods rich in complex carbohydrates.
All major health advisory bodies, including the World Health Organisation, agree that most people in the West eat too much fat to be healthy.(60) Fat, especially saturated fat – which mostly comes from animals – increases the risk of heart disease, diabetes and some cancers.
High in calories and not very filling, it’s no great surprise that fat is a primary cause of weight gain.
A low-fat diet, on the other hand, boosts good health and is the best way to control weight.
The main sources of fat are shown in Figure 4, with meat and meat products in poll position. Not only are we eating meat in unprecedented amounts but modern farming methods have ensured that its fat content has doubled.
Professor Michael Crawford, of London Metropolitan University, recently analysed chicken thigh meat from several supermarkets – including organic suppliers. He found they contained more than twice as much fat as they did back in 1940 and had around 100 kcal more.(61)
Today’s beef was found to contain 30 per cent fat compared with the five per cent in wild beef. The reason is the standardised, industrial feed now given to farmed animals, designed to produce maximum weight gain. Chickens, for example, reach slaughter size almost twice as quickly as they did 40 years ago.
Researchers at the American Cancer Society followed more than 75,000 people for a decade to find out what is was that caused their weight loss and weight gain.(62) High meat consumption was the food most responsible for them putting on weight.(62) Whether men or women, if they had more than a single serving
of meat a day, they showed a 50 per cent increase in ‘abdominal obesity’ – they put on the pounds around
From the 1980s onwards, it became common for butchers and processors to trim from meat any visible fat as part of the demand for leaner meat. It didn’t have much effect as people’s fat intake from meat has dropped by a mere five per cent since 1983.(63, 64)
As Professor Crawford explains: “Rapid growth [in intensive, factory farming], achieved through a high-energy, cereal-based diet has changed the lipid (fat) composition of the chicken meat itself, and you cannot escape that – even by removing the skin and scraping away the subcutaneous fat stuck to the meat.”(65)
Meat and meat products are the leading source of fat in people’s diet while milk and milk products, such as cheese and semi-skimmed milk, are not far behind, making up 14 per cent. Animal fat from butter and milk is also a major ingredient of cakes, pastries, biscuits and chocolate. Vegetable oils, and often harmful hydrogenated oils, are also used.
Perhaps it’s not surprising that cereals and cereal products, especially manufactured goods such as pizza, biscuits, buns, cakes and pastries, make up just under one-fifth (19 per cent) of fat intake.
Your body can’t function without some fat – but it’s the right kind that’s important. We don’t need saturated animal fat as it causes higher levels of cholesterol, hardening of the arteries, heart disease and strokes. Figure 5 shows where most saturated fat comes from – animal products!
The fats which are essential are linoleic acid (omega-6) and alpha linolenic acid (omega-3). Called ‘essential’ fatty acids, they are vital to cell structure, regulate the way cholesterol is carried, broken down and excreted and are also involved in hormone functions. Seed oils such as linseed (flax), rapeseed (canola) and walnut oil are rich sources, as are the seeds and nuts themselves.(66) Green leafy vegetables are also a source.(67)
As part of a healthy diet, the Food Standards Agency encourages people to reduce the amount of hydrogenated and saturated fat they eat and replace them with unsaturated fats.(68) It means cutting down on fatty meat, dairy products (cheese, cream, chocolate etc) crisps, rich cakes and biscuits.
Dairy milk can be replaced by calcium enriched soya, oat, nut or rice milks. Use small amounts of olive or rapeseed oil in cooking instead of butter or lard and switch to dairy-free margarines.
Not only is it important to cut back on these types of fat but also to reduce the total amount of fat that you eat. One to two handfuls of nuts and seeds (flax, walnuts, hemp) or one teaspoon of flaxseed oil each day should provide you with all the omega-3 fats that you need.(69)
Sugar, Pop and Alcohol
There has been an increase in the consumption of sugary drinks and there is growing evidence that they may be fuelling the increase in obesity.(70) Rather than replacing other foods, they add to them, increase the risk of eating too many calories and are a particular problem for children, who drink the most.(63, 71) Instead of these sugary drinks, drink up to two litres of water each day. Water contains no calories!
Table sugar, sweets and syrup are rich in a type of carbohydrate called simple carbohydrate (or simple sugar). In contrast, starchy foods like brown rice, oats, barley and rye contain complex carbohydrate. The role of both types of carbohydrate in obesity has been looked at(72, 73) and it’s been found that when either type replaces fat in the diet, it could help weight loss.
The problem is that sugary foods quickly release their sugar into the bloodstream and can reduce the levels of HDL (good) cholesterol and increase levels of LDL (bad) cholesterol.(74) They can also increase your risk of diabetes and heart disease.(74) Even glucose, the main sugar in your blood, has the ability to damage blood vessel cells(75) so complex carbohydrates (which release their sugars more slowly) are a better choice than simple carbohydrates (such as white and brown sugar).
To get your share of complex carbohydrates, eat three or four servings of grains each day, such as pasta, rice, oats and bread and choose wholegrain varieties rather than the refined, white versions, which are best avoided as a lot of the nutrients have been stripped out.
The effect that alcohol has on weight isn’t clear-cut. It contains many more calories than carbohydrates (seven kcal per gram compared with four kcal) and some alcoholic drinks also contain sugar or are served with other drinks that contain it, such as mixers.
Alcohol consumption in the UK has doubled between 1960 and 2002.(76) Like soft drinks, alcohol obviously doesn’t cut the number of calories you take in(77) but despite this, the Health Survey for England showed that nondrinkers are more likely to be obese than those who booze!
Most of what’s known about alcohol’s effect on weight isn’t very scientific and doesn’t answer some obvious questions. For example, is smoking tobacco at the same time as drinking responsible for the ‘slimming’ effect? If you do drink, the advice is to limit it to less than two drinks a day for men and one for women.
‘Energy density’ refers to the amount of calories that different foods contain, weight for weight (kcal/100g). For instance, traditional African diets contain approximately 108 kcal per 100g and as a species this is probably the level we have evolved to best cope with when it comes to regulating our weight.(83)
Most plant foods, such as boiled grains, lentils or beans, provide under 120 kcal per 100g and most fruits and vegetables provide much less than this.(84)Together, these foods are pretty close to the optimum for density.
‘Energy dense foods’ and ‘energy dense diets’ have been blamed for the global obesity epidemic.(78-82) These high-calorie foods are less filling and so encourage snacking, leading to overeating and weight gain.(85) They also tend to be low in essential nutrients.(85)
Compared to protein and carbohydrate, fat is the most energy dense (or highly calorific) and the least filling.(86)To feel full, you need to eat more than if you were eating a low-fat, high-carbohydrate food.
When people are offered foods in which the fat content has been secretly pumped up, they eat more of it than a similar food that has a low fat content.(87) The body simply appears not to recognise that it is eating more calories and as a consequence, weight gradually increases. On a low-fat, much lower calorie diet, despite eating as much as they want and never feeling hungry, people still tend to lose weight.(87)
The amount of fibre in foods has a direct link with feeling full.(86) It requires longer chewing, expands the stomach more, hangs around there for longer and leads to a slower, steadier release of nutrients.(86) Prolonged chewing slows the rate at which you eat and gives the body a chance to recognise how much food it is taking in and curb it.
As the stomach stretches, natural receptors trigger the feeling of being full to slow your eating down. It’s been shown that every 14 grams of extra fibre in the diet – the amount in an average portion of bran cereal plus a small can of beans – reduces calorie intake by 10 per cent.(88)
Protein is the most filling nutrient of all (89,90) which is why high-protein diets such as Atkins came into being. But there’s no absolute proof that it’s protein per se that’s responsible for weight loss in Atkins-style diets – monotony (boredom from the tight restrictions on what you can eat) and ‘ketosis’ may play a part.(86) Ketosis happens when the body is short of glucose – the fuel needed to power the breakdown of body fat. Lacking glucose, the liver releases acidic substances (ketones) into the blood, much as happens in type 2 diabetes. But careful studies have shown that ketosis is unrelated to weight loss. In other words, low-carb diets do not trigger weight loss any more effectively than low-fat, vegetarian diets do.
While a few studies show that high-protein, low-carbohydrate diets do produce some weight loss early on,(91-93) the long-term health consequences can be very serious.
Most of these diets contain less than 10 per cent carbohydrates, 25 to 35 per cent protein, and 55 to 65 per cent fat.(94) Most of the protein comes from meat, meat products and dairy, which are high in unhealthy saturated fat and cholesterol. As they contain so much more fat than protein, a better name would be ‘high-fat’ diets.(94)
Over 400 people who followed one of these diets listed their health problems in an online registry.(95) They included constipation, loss of energy, bad breath, difficulty concentrating, kidney and heart problems, including heart attack, bypass surgery, irregular heart beat (arrhythmia) and raised cholesterol.(94)
Of course, plants also contain protein, but plants rich in vegetable protein are low in the harmful saturated fat that increases the risk of heart problems. Good protein sources include pulses such as baked beans, peas, lentils and soya products, grains, nuts and seeds. They have the added bonus of being rich in fibre and eating two to three servings of these foods each day is recommended.
Dairy and Weight Loss
When nine scientific studies were looked at by researchers to see if dairy or calcium supplements could reduce weight,(100) they found no evidence. In fact two showed they increased weight and the other seven showed they had no effect. A recent huge study involving 12,000 children over a three-year period found that those who drank the most milk gained the most weight.(101)
Dairy products such as cheese, butter and cream are exceptionally high in saturated fats (over 60 per cent of the fat in cheese and butter is saturated fat!) This type of fat is the unhealthy kind which raises bad cholesterol levels, increases the risk of heart disease and strokes, and which can obviously lead to weight gain.
SUMMARY & ACTION POINTS
• Obesity happens when people eat more calories than they need.
• Men need about 2,550 kcal a day – women 1,940 kcal.
• Minimum intake should be 1,500 kcal for men and 1,200 for women.
• Animal products are the main source of fat – and particularly bad saturated fat.
• One serving of meat a day can put on weight around your waist.
• Children who drink the most milk gain the most weight.
• Lose weight by replacing meat and dairy with plant foods.
• Jettison junk foods.
• Dump foods that contain saturated animal fat or damaging hydrogenated vegetable fat.
• Get your ‘essential’ fats easily from nuts and seeds or their oils.
We all know that most of us don’t take as much exercise as we should, mostly because our jobs don’t require it. Information technology, the car, labour-saving devices, lifts, automatic doors,TV and computer games and warmer houses all play a part.(6) And it’s much the same for children.
A huge government survey in the year 2000 should have shocked the nation. The National Diet and Nutrition Surveyshowed that most young people between the ages of seven and 18 were inactive and spent little time on even moderate, let alone vigorous, activities.(71)
In the 1970s, 90 per cent of primary school children in the UK walked to school, compared with 10 per cent today.(102) And in 2002, less than half of English children met the government’s target of two hours PE (exercise) a week.(6)
It’s blindingly obvious to say that more activity helps with weight control. People who exercise the most are the least likely to be obese.(103) Just as importantly, people who are the most physically active gain less weight as they get older than those who are sedentary.(104)
The Chief Medical Officer recommends that adults get at least 30 minutes exercise a day; it should be at least moderately-intense and it should be on at least five days every week.(105)Young people need even more than this – a minimum of 60 minutes every day – and should include bone-strengthening exercises at least twice a week such as walking, running and climbing.(105) Older people should keep moving and keep mobile through daily activity, including improving strength, coordination and balance.(105)
These targets can be achieved in one session or in several shorter bouts of 10 minutes or longer each.
You needn’t don lycra and sweat it out at the gym, particularly if the mere thought of it is enough to bring you out in a cold flush! Walking can be a great way of keeping fit and improving your health – and you can use it to meet the Chief Medical Officer’s recommendations.
There is one big ‘but’ – you need to take 10,000 steps a day. If you notch up this total you are likely to have less body fat(106, 107) and lower blood pressure.(106)
A pedometer is a great motivator and helps you keep score. Clipped to your waistband, it not only counts your steps but can measure the calories you’ve burnt off and the distance you’ve walked.
For young people, 10,000 steps a day is probably too low and girls should aim at 11,000 while 13,000 is the goal for boys on at least five days a week.(108)
You can check your level of activity with the table in Figure 6. If you’re way short of the 10,000 steps a day target, build up slowly, adding 500 to 1,000 steps a day. Easing into the changes makes it more likely you’ll stick to them and less likely you’ll do yourself an injury.
Work to notch up the extra steps:
• Park at the far end of the car park when shopping.
• If you need only a few things from the shop, use your legs instead of the car.
• Don’t go round the supermarket or shops in a logical order – you’ll be amazed how far you can walk by going back and forth.
• Take the stairs instead of the lift or escalator.
• Get up from your desk at work little and often.
• Give the dog an extra 5 minutes walk – or borrow a neighbour’s dog if you don’t have one!
• At work, walk to get your lunch or to find somewhere to eat it.
• Walk to the corner shop instead of driving.
• Hop off the tube or bus a stop early.
Average out over seven days the steps you have walked each week and monitor your progress until you reach your target (Figure 7).
The next section is our V-Plan Diet One Week Meal Plan. Enjoy losing weight the healthy way and let us know how you get on. Write to the Viva!Health at 8 York Court, Wilder Street, Bristol, BS2 8QH or email us at firstname.lastname@example.org.
SUMMARY & ACTION POINTS
• Exercise is essential but many people don’t get enough.
• Exercise helps control weight and can reduce body fat and blood pressure.
• Walking can be as good as a work out – but you need to take 10,000 steps a day.
• If you’re short on steps, there are simple ways of increasing your walkabouts.