The terms ‘overweight’ and ‘obese’ are most simply defined as an abnormal or excessive accumulation of fat that will impair health. Using definitions of overweight and obesity, World Health Authority data has demonstrated that world wide obesity almost tripled between 1975 and 2016, with 1.9 billion adults over the age of 18 being classed as overweight. Of these, 650 million were classed as obese. Of great concern is the fact that, in 2016, 41 million children under the age of 5 were classed as overweight or obese, and 340 million children/adolescents between the ages of 5 and 19 were overweight or obese. The WHA states most of the world's population live in countries where more deaths arise from conditions relating to overweight and obesity than they do from being underweight.
Body Mass Index (BMI) is used as a tool for determining the actual risks to an individual of being overweight or obese. This tool is a simple index of weight-for-height (calculated by dividing a person’s weight in kilograms by the square of their height in meters (kg/m2) and is used alongside charts to determine their relative health risk. The World Health Authority definition of being overweight is having a BMI greater than or equal to 25, and their definition of obesity as having a BMI greater than or equal to 30. For children and teenagers different criteria apply which take into account the differences in body fat between girls and boys as well as differences at various ages.
Unfortunately, the explosion of obesity rates has also had a significant impact on health. Raised BMI is a major risk factor for cardiovascular diseases, diabetes, osteoarthritis as well being associated with certain cancers such as those affecting the breast and colon. In Europe alone, it is estimated that obesity or being overweight contribute to at least 1 in 13 of every deaths. Sadly the future health of our children will also be affected by rising obesity rates - as many as 41 million children, younger than 5 years of age, were defined as being overweight in 2016, a figure which is rapidly increasing.
Disturbingly, although being overweight or obese was once considered a problem in wealthier countries, it is now rising in lower and middle-income countries. Between 2000 and 2016 in Africa, the number of overweight children under 5 increased by almost 50%. Whilst nearly half of the children under 5 classed as overweight or obese in 2016 lived in Asia.
Some causes of obesity include genetics, diet, exercise, lifestyle choices, psychology, disease and disorders. Before we can devise an appropriate intervention for weight loss it is necessary to consider when and how we gain weight.
Portion control is an essential element of any effective dietary plan. Various studies have shown that our portions have increased over the years. Added to this is the fact that where we are presented with more foods on our plates than we require most people will eat more without thinking of it.
There are many reasons why food portions have increased. A significant reason is the increased availability of food and competition between food manufacturers and restaurants to sell more of their products. Our food portions can also be adversely influenced by those around us. For example, some people will indicate that their food portions increased when they first left home and ate with friends in school/college, while others will say their food portions increased after getting married/starting to live with another person.
How can we begin to address portion size?
Firstly, the good news is that most people will still feel satisfied when they eat less, although they may need to be convinced of this. For example, one study rated customer satisfaction following a pasta meal in a restaurant. Here some customers were served a standard portion while others were served a portion that was 50% larger. The study found that many customers served the larger meal ate nearly all of it consuming 720.13kJ more than those served the standard portion. Interestingly, while those served a larger meal ate more of it, survey responses showed that customers rated the size of both portions as equally appropriate to their needs.
General tips to help clients reduce portion size
- Try eating a salad or vegetables before a main meal or making it a significant part of the meal (about half of the plate size). This will help you to feel fuller sooner as vegetables are low in KJ and also a good source of fibre which helps to fill us up.
- Snack foods can be high in kJ and can come in large portion sizes e.g. a large bag of tortilla chips or crisps can be almost as cheap as smaller packs. In view of this try to split full sized packages into smaller individual portion bags and containers.
- Watch your plate size. Our portion sizes have increased along with increases to our dinner plate size. You may wish to buy a smaller plate or a child’s plate to reduce your portion size. Also consider asking for a child’s serving when eating out. Many restaurants also now tend to offer lower calorie meal alternatives, for example burgers without buns, or salads instead of fries.
- >Save your leftovers and keep seconds out of sight. If you have cooked too much for a main meal avoid the temptation to overeat by distributing leftovers into freezable containers to consume at a later date.
As we have said, portion size is a crucial part of weight control, however in addition to considering the portion of food we serve up, we must also consider the energy content of this portion (i.e. how many kilojoules the food contains). Here we need to consider the energy density of food items working on the principle that some foods provide more joules to volume than others. For example, fruits and vegetables have a high content of water and fibre and are low in fat causing them to have a much lower energy density than energy dense foods such as cakes and biscuits. By concentrating on energy density consider what foods you are eating as well as the amount you are eating.
Fats and energy density
It is impossible to consider energy density without giving consideration to the amount of fat in our foods. Fat itself provides around 9 kcls per gram which is over double the joules provided by protein and carbohydrates which provide around 4 kcals per gram. The increasing presence of fats in our diet has made this nutrient a major contributor to rising rates of global obesity.
Sources of fats in our diet
Fats are found in foods such as butter, margarine, oils, meat, fish, nuts, seeds and processed foods.
There are three main types of fats in our diet:
- Saturated fats are found mainly in animal products and processed foods such as in meat, dairy, eggs, cakes, biscuits and pastries. Saturated fats do the most damage to our health as they are most related to the build up of unwanted LDL (low-density lipoprotein) cholesterol in our arteries.
- Monounsaturated fats are found in olive oil, canola (rapeseed oil) and peanut oil and help to decrease LDL cholesterol levels in our blood.
- Polyunsaturated fats are found in oily fish, vegetable oil, palm oil and products made from these. In small quantities polyunsaturated fats can help to decrease total cholesterol. As far as weight loss is concerned it is important to realise that all fats have the same amount of joules and need to be restricted while restricting saturated fats in particular will be most beneficial to your health.
General tips to reduce fat
- Reduce saturated fat e.g. butter, cream, fatty meats, cakes, biscuits and fried foods.
- Choose leaner meats where possible and trim off the visible fats before cooking.
- Select lower fat dairy foods e.g. skimmed/ semi skimmed/ half fat milk and reduced fat cheese such as edam, ricotta, cottage cheese and mozzarella.
- Beware of hidden fats in processed foods by checking out food labels for the fat content of foods and noting the presence of fats on the ingredients list. Remember here that fats are also known by other names e.g. as lard, coconut oil, palm oil, vegetable oil, whole milk solids, margarine, cocoa butter and animal shortening.
- Include some unsaturated fats in your diet in measured quantities e.g. olive oil, nuts, oily fish and avocado.
- Swap high fat salad dressings such as French dressing and mayonnaise with vinaigrette or lemon juice.
Increased calorie intake "might" cause increased weight; but this is not necessarily so.
The type of calories eaten will be significant in affecting weight.
It is an efficient metabolic process to convert triglyceride fat molecules from foods, into triglyceride molecules stored in body fat.
It is NOT so efficient for the body to convert protein or carbohydrate molecules into body stored fat molecules.
Because of this ... fats are more fattening than carbohydrates or sugars.
Low calorie dieting
Eating very low quantities of calories is ineffective in reducing weight; and can be dangerous to health. Side effects of calorie deficiency can include:
- Feeling depressed or deprived.
- Excessively strong cravings for food.
- Low calorie diets (also called crash diets) may in fact encourage binge eating, which can exaggerate obesity problems.
- A pattern of crash diets followed by binge eating is called "weight cycling". This may lead to replacement of muscle tissue with adipose tissue, and it may not result in any significant long term change in body weight.
Abdominal obesity has been linked to insulin resistance (i.e. sufficient insulin is produced, but insulin receptors in the cell membranes are not responsive enough to that insulin, hence blood insulin levels are increased. This in turn may lead to fluid retention, and raised blood pressure. Weight loss may help bring insulin back into balance. (NB: Extra fat in the hips and thighs is not normally associated with insulin resistance).
Learn more to improve diet and long-term health
Knowing some facts may be helpful, but knowing about nutrition and the way the body works is the only way to effective dietary control.
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