While not actually measuring the percentage of body fat, it is used to calculate whether a person is underweight, a healthy weight, overweight or obese for their height. It allows for natural variations in body shape, giving a healthy weight range for a particular height.

The calculation divides the adult’s weight in kilograms by their height in meters squared.

BMI Calculator

Numerous tools are available for calculating BMI. But we prefer this tool from the NHS and can calculate BMI for children.

NHS Healthy Weight Calculator

Note: Most widely available BMI calculators are for adults only.

BMI Categories

• BMI 16.5 or below: Severely underweight
• BMI 16.5-18.4: Underweight
• BMI 18.5-24.9: Healthy weight
• BMI 25-29.9: Overweight
• BMI 30-34.9: Obesity
• BMI 35 or higher: Extremely obese

Children’s BMI Results

For children, BMI is interpreted differently.

While the calculation is the same as for adults, the age and sex of the child are also taken into account. Instead of set ranges (as shown in the BMI Categories above), children’s BMI uses percentiles to assign whether a BMI is within a healthy range according to height, weight, age and sex.

By comparing the values to other children of the same age and sex, an overweight BMI means it is higher than average for a child of their age and sex.

Limitations of BMI

BMI is a simplistic calculation dependent on weight and height only. Therefore it does not take into account many factors, such as, muscle and bone mass. While widely used and respected, the medical community generally acknowledges these shortcomings.

Individuals who may be given an inaccurate BMI are athletes, children, the elderly, the infirm and naturally endomorphic or ectomorphic people ( people who do not have a medium frame).

According to their BMI, children and the elderly tend to be “underweight” because of the differences in bone density. To factor in the proportion of bone to total weight, their BMI should be adjusted downward or the use of a special scale for determining BMI (as described in Children’s BMI Results above).

Athletes tend to be “overweight” or “obese” according to their BMI. Because muscle weighs more than fat, a modified version is sometimes used to adjust the ranges upward. Alternatively, there are better methods for determining the body composition of athletes. For instance, body fat can be calculated using techniques, such skinfold measurements or underwater weighing.

Other BMI inaccuracies can occur. For instance, a tall person with a small frame and excess fat around the waist may show a normal BMI. Therefore, if you have any questions about your results, consult your doctor who may want to employ another measuring device to double-check your findings.

How Does Exercise Positively Affect the Brain?

Aerobic exercise causes a mild stress on the body by threatening its energy reserves. Our body responds by protecting the brain.

Neurons in the brain die if deprived of energy for more than a minute. Given the vulnerability of one of our most valuable organs, the body is designed to protect it. One way it response is by releasing brain-building growth factors, according to Carl Cotman, Director of the Institute for Brain Aging and Dementia at the University of California.

Significantly exercise not only protects our brain but also improves brain function.

Why It Works

Regular updates about our body are sent to the brain whenever there is a change. When we walk, our bodies send electric messages about our knee bending, straightening and so on. When we move fast enough, there is no space between each message causing a build-up in the brain. And this build-up triggers a release of chemicals called growth factors.

Growth factors cause new neurons to form and old ones to grow and form better connections with each other. Blood vessels, beside the neurons, blossom giving the neurons quicker access to glucose and other nutrients. Resulting in an improvement in our ability to think, learn and remember.

How Much Exercise Causes the Response?

Daily exercise is not necessary. Exercising every other day for at least 30 minutes works just as well. Provided it is aerobic exercise and not anaerobic, such as weightlifting, then you too could become smarter while getting fitter.

We live in centrally-heated rooms, cleanse our bodies externally and internally with chemically treated water and breathe air laden with petrol fumes, chimney grim and atomic spillage. How our bodies cope depends a lot on what we do minimize the harm we do.

What Difference Does it Make

How you look and feel is entirely down to the choices you make. Eat rubbish and you’ll pile on the weight and years. Yet simple changes every day to your diet, exercise and lifestyle will boost your energy levels and minimize many problems.

And it isn’t always about weight. What we do can help us achieve radiant-looking skin, glossy hair, strong teeth and healthy nails.

What Our Bodies Need

Our bodies’ needs can be grouped into four main categories: air, diet, sleep and exercise.

Air

We need air – ideally, fresh air – to breathe to keep our respiratory system functioning. Oxygen in the air is vital for our organs to survive and is sent to all parts of the body via the blood. The constant action of the heart pumps oxygen-rich blood and essential nutrients through our blood vessels.

Problems begin when obesity, alcohol, drugs, nicotine and lack of exercise thickens the walls of our blood vessels constricting the free flow.

Balanced Diet

Our diet has a direct impact on how we look and feel. A balanced diet full of the right foods in the right proportion can help us stay fit, healthy and full of energy. Depending on what age and stage of life you are in, you’ll need varying amounts from these essential groups:

• Carbohydrates – choose more complex carbohydrates with fibre and not simple ones such as sugar or chocolate.
• Fruits and vegetables – a variety of different colours will help you get a range of valuable vitamins and minerals. Eating a whole fruit with skin provides fibre and more sustained energy than a fruit juice.
• Protein – both vegetable and animal. And try to eat more fish.
• Milk and dairy
• Fatty acids (more during the growth phase of your life and less for maintenance) – poly-unsaturated rather than saturated fats.
• Minerals – especially vitamins, calcium and iron, and less salt. Most importantly vitamins C and B complex, which are soluble in water, and so, must be replenished daily.

If you’re unsure what a healthy plate looks like check the British Nutrition Foundation’s Eatwell Plate.

Sleep

Sleep restores the body. During this period of rest when the brain’s activities slow down, the body’s chemistry gets to work. It processes nutrients, and heals and repairs tired and damaged tissues.

Limbs and muscles relax and the skin smooths out, temporarily erasing wrinkles and worry lines. Cells can return to their restorative work because body energy is not diverted to anything else.

Caring for our body includes listening to the signals it sends to take a rest. A bath or shower before bed partly helps relax muscles and allows the skin pores to breathe. You will also benefit from a good night’s sleep. Some people need a little more and others a little less, but try to aim for eight hours.

Exercise

Regular exercise contributes to a general feeling of well-being. It is rarely successful as a slimming aid on its own but other advantages include:

• Improves circulation
• Speeds up digestion
• Keeps muscles and limbs supple
• Clears the mind

Exercise doesn’t have to be done in a gym. A brisk, thirty minute walk every day to work can often fit better into our busy schedules and is enjoyed more than sitting on a stationary, gym exercise bike.

Remember the saying – what you put into your body is what you’ll get out of it. Looking and feeling as fit and healthy in your 50s as you did in your 20s means simple changes now.

• Low-fat, average-protein: 20% fat, 15% protein and 65% carbohydrates
• Low-fat, high-protein: 20% fat, 25% protein and 55% carbohydrates
• High-fat, average-protein: 40% fat, 25% protein and 40% carbohydrates
• High-fat, high-protein: 40% fat, 25% protein and 35% carbohydrates

All diets included 8% or less saturated fat, at least 20 g of dietary fiber per day and 150 mg or less of cholesterol per 1000 kcal. Participants were also encouraged to exercise 90 minutes per week.

What Were the Results?

After six months, all the participants lost an average of 13 lb/6 kg, approximately 7% of their starting weight. After a year, they regained some of the lost weight. And by 2 years, weight loss was approximately 9 lb / 4 kg. Regardless of which diet, participants also experienced similar levels of satiety, hunger, satisfaction with the diet and attendance at group sessions. They also lowered their risk of diabetes and improved heart health by reducing blood levels of bad cholesterol (LDL) and increasing good cholesterol (HDL).

Dr. Frank Sacks, a professor at the Harvard School of Public Health and lead author of the study, believes: it doesn’t matter where your calories come from, as long as you’re eating less.

Recommended Calories Per Day

During the study, researchers urged participants to eat 750 calories less than they used each day. And for the first several weeks, dieters followed that advice. However, at six months, they were only consuming 225 calories less.

The main reason for the increased intake was hunger. New thinking by the researchers is that a more gradual change in intake may be better or maybe a more realistic reduction in calories would be the best approach.

Overall, the good news is that you can take a flexible approach to picking a diet. Choosing a diet that fits your lifestyle and eating habits has the best chance of success – provided you are eating fewer calories than you are burning. And setting realistic goals will ensure long-term success.