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Weight Loss/Management
In the majority of adults there body mass or weight remains relatively constant over a year, generally varying by less than 3-4kg. For these individuals there is an equal balance between there calorie intake, from food and drink, and their energy expenditure through physical activity. If these individuals were to then increase their calorie intake and, or, decrease their physical activity levels, there intake of calories would be in excess of energy expenditure. The excess of calories would then lead to increased storage of body fat and would cause an increase in body weight. If on the other hand they reduce their calorie intake and, or, increase physical activity levels they would have a net expenditure of energy. Because more energy is being used than supplied, through the diet, the body then turns to its stores of body fat to use as fuel. This would therefore lead to a decrease in body fat levels and body weight. In the western world there are increasing levels of obesity. Obesity, is essentially, the storage of an excessive amount of fat. A man is classified as obese if they have a body fat percentage of 25% or greater, and the limit for women is set at 30%. Obesity is linked to many health problems including: type II diabetes, high blood pressure, heart disease, and a reduction in healthy lifespan. It is estimated that around 20-25% of the adult population, within western society, can be classified as clinically obese. Perhaps, more worryingly, the level of obesity among children is also rising. Although, for some people the cause of obesity is genetic, for the vast majority of people, is due to poor diet and reduced activity levels. For people who are suffering with obesity or those looking to increase weight loss there are three methods they can use:
Dieting for weight loss It is generally recommended that people looking to diet for weight control/loss purposes should reduce their calorie intake by between 500-1000 calories. It is well known that diets with greater calorie reductions are more likely to lead to failure as people using highly restrictive diets tend to put their weight back on far more quickly than those who follow a controlled diet and loose have a more gradual weight loss. Large reductions in calorie intake (diets containing only 1000 calories or less) are far more likely to result in large reductions in stored water and glycogen (a type of carbohydrate or sugar), with only small reductions in body-fat levels. Research has demonstrated that supervised weight loss programmes can result in a 10% reduction in body mass (the equivalent of going from 11 stone to around 9 stone 13 lbs). However, you should bare in mind that most diets are unsuccessful in the long run and even supervised dieters will put on around half of their weight within a year. More discouraging is the fact that more than 90% of diets fail in the long run, regardless of the type of diet.
Effect of dieting on metabolic rate One particular problem that occurs with dieting is a significant reduction in metabolic rate. If your metabolic rate decreases then your body requires less energy for normal functioning and therefore unless you restrict your calorie intake, still further, you will be likely to fail to loose more weight or even put the weight back on. With severe dieting the metabolic rate may decrease to around of normal this would have a very negative effect on weight loss. If we use the example of a woman who reduces her calorie intake, by more than 1000 calories, to just 900 calories a day. Initially she looses a lot of weight although most of the weight she looses is just stored water and glycogen which she will quickly put back on as soon as she returns to a normal diet but after a while her metabolic rate slows to the point where she only needs 1000 calories a day. In this case even though she is consuming around 900 calories a day, her body now needs just 1000 calories a day to maintain normal body size and she is unlikely to loose a significant amount of additional body weight. An additional problem, is that her metabolic rate will not quickly return to normal, when she returns to her normal consumption of 2000 calories a day. In this case, if she now consumed 2000 calories a day she would be consuming 1000 calories more than what her body actually needs. Consuming around 1000 extra calories a day, would lead to a 2 pound gain in weight over a week. However, the actual weight she would put on, when returning to a normal diet would be even higher as she would quickly put on all the weight she lost from water and glycogen early on in the diet. This is why people who come of strict diets may put on as much as 6 pounds in one week once they return to their normal eating habits. Another factor two consider is that highly restrictive diets will lead to a reduction in muscle mass. Since lean muscle is metabolically active, any reduction in muscle mass will lead to additional reductions in the metabolic rate and make dieting less successful. A reduction in muscle mass, occurs through dieting because the body breaks down muscle tissue to use as an energy source because it isnt getting enough energy supplied through the diet. Therefore the lower dietary intake the greater the loss of muscle mass will be. By using a controlled diet reducing your calorie intake by around 500 calories a day you will be less likely to lower the metabolic rate, or loose muscle mass, and therefore will be more successful in the long run. A controlled dieter could expect to loose 1-2 pounds of fat per week.
Variations of diets Low carbohydrate diet: This involves greatly restricting your carbohydrate intake. The idea is that by greatly restricting carbohydrate intake you force the body to mobilise fat tissue from around your body to be used as energy. Advocates of the low carb diet believe that it suppresses the appetite and has an extreme weight loss effect. However, research does not support the claims and most of the early weight loss is likely to be through the loss of water rather than fat. This type of diet also leads to significant loses of lean muscle and therefore has a negative effect on the metabolic rate. This type of diet may have a number of adverse side effects including: dehydration, heart abnormalities, raised blood cholesterol, and very low energy levels. High Protein diet: supporters of this diet believe it to raise the metabolic rate, increase fat metabolism and suppress the appetite. It is known that protein intake can have a positive effect on metabolism. It is also believed that the low digestibility of protein make it less likely to be stored as fat. However, dieters are likely to see better effects through a controlled diet contain around 60% carbohydrate, 30% protein, and 10% fat. The high protein diet can have the following side effects: dehydration, heart abnormalities, kidney problems, raised blood cholesterol, and very low energy levels. Although it would not be wise to base a diet around an excessive consumption of protein, increasing protein intake slightly possibly through the use of protein shakes between meals will have a positive effect on metabolism and may aid weight loss.
Basic Dietary Recommendations
Carbohydrate Intake Try not to have an excessive carbohydrate consumption although adequate carbohydrate consumption is important for proper metabolic functioning an excessive consumption, above what your body needs, for normal functioning, will be stored as fat. When there is an excessive consumption of carbohydrate the body responds by releasing large amounts of insulin. Insulin is responsible for moderating blood sugar levels. When the body detects large amounts of sugars in the blood it responds by releasing insulin to control the blood sugar level. The excess of carbohydrate will then be taken up by muscle cells, and more worryingly from a health perspective, it will encourage the body to store the excess as fat. Another problem associated with the insulin response to excessive carbohydrate consumption is that, in relatively inactive individuals, the insulin will cause blood sugar levels to drop considerably and may lead to low blood sugar levels i.e. the body overcompensates for the amount of sugar in the blood. This drop in blood sugar levels normally occurs, 1-2hours after the consumption of carbohydrate, and is associated with a significant drop in energy levels. This is why many people who consume junk food such as a bar of chocolate, in order to raise energy levels, often find that their energy levels are only raised for about 30-60minutes. After this initial rise they normally find that their energy levels drop off significantly, to a level that is lower than what they were originally. This rise in insulin levels can be caused by either the consumption of high energy foods such as chocolate bars or through the consumption of excessive amounts of carbohydrate with meals. In order to reduce the insulin response you look to reduce your consumption of junk food such as chocolate bars, and also look to reduce the amount of carbohydrate that you consume with meals. A good way to reduce the amount of carbohydrate you are consuming at any one time, and to increase your energy levels, is to consume several smaller meals throughout the day rather than 3 large meals. Maybe look to have 5 smaller meals during the day. If you consume these every 3 hours it will help to maintain your energy levels and will help to lower the amount of insulin that is released. You should also look to cut down the amount of carbohydrate that you consume with each meal dont have more than 50-75g of carbohydrates such as pasta, rice etc with any meal. Often people make the mistake of adding additional sources of carbohydrate to a meal, such as noodles to a stir-fry, when there is likely to be plenty of carbohydrates present within the vegetables in the stir fry. Also, when you do consume carbohydrate, try to use the more complex carbohydrates such as brown rice, wholemeal bread, and pasta rather than the processed versions such as white bread, or quick cook pasta. The advantage of complex carbohydrates is that they take longer to digest and therefore they release their sugars at a slower more controlled rate. This keeps blood sugar levels more even and will be less likely to lead to a sudden rise in blood sugar levels. Another consideration is the time of day that you consume carbohydrates. It is important to consume some slow releasing carbohydrate, first thing in the morning, such as porridge. This helps to speed up your metabolism, after it has slowed down overnight, and because porridge contains slow releasing sugars it helps to maintain energy levels for several hours. As we get to late afternoon/early evening our metabolism starts to slow down and therefore you should look to reduce consumption of carbohydrates late in the evening ideally no later than 6pm as this is much more likely to be stored as fat. If you are going to eat later at night try to consume more protein rich foods as these will help to raise your metabolism.
In Short:
Protein Intake Ensure you have an adequate intake of high protein foods such as chicken, turkey, beef, and fish. A low protein intake is associated with low metabolism and therefore it is beneficial to increase your intake of these foods. You should look, in particular, to include high protein foods such as tuna and turkey which are both particularly high in protein and have the added benefit of being low in fat. Also by mixing protein with carbohydrates you will help to slow down the absorption of the carbohydrates and this will help to stabilise blood sugar levels. Consider having small meals of tuna and pasta (ideally only 50-75g of pasta) or turkey/chicken stir fry with vegetables but no noodles.
In Short:
Fat Intake Whilst it is important not to have an excessive intake of fat (90g per day for men and 75g for women) you need to ensure you are consuming enough of the healthy essential fatty acids. Essential fatty acids are known to increase the rate of fat metabolism, as well as decreasing the storage of additional body fat. There are two types of essential fatty acid, omega-3 and omega-6. Both have positive effects on our health including: 1) a lowering effect on body fat by increasing the rate of fat metabolism and decreasing the storage of body fat, 2) they also help to and normalise hormone levels, 3) improve brain function, 4) lower or normalise blood pressure in people with slightly raised blood pressure, 5) lower cholesterol levels and therefore reduce the rate of arteriosclerosis (furring of the arteries). Therefore, ensuring an adequate dietary intake of essential fatty acids may help to lower body fat levels and improve your general health. Good dietary sources of essential fatty acids include: 1) many nuts and seeds such as almonds, sesame seeds, and pumpkin seeds are high in the Omega-6 essential fatty acid; 2) many oily fish specifically herring, mackerel, and sardines are high in the essential fatty acid omega-3; 3) many oils, specifically, sesame oil, olive oil, flaxseed oil and borage oil are particularly high in essential fatty acids you should always look to include unprocessed oils as they contain more essential fatty acids.
In Short:
Exercise for Weight Loss Current research suggests that the current obesity epidemic is more to do with a reduction in physical activity levels rather than excessive consumption of food. In the United States calorie intakes have been decreasing by 5-10% yet body mass has increased consistently. Therefore, in the case of the United States population, the increase in obesity cannot be attributed to calorie intake. Most experts now consider exercise to be of greater benefit to weight loss than dieting. One of the big advantages of exercise is that not only do you burn more calories during the exercise but your metabolic rate is increased for several hours after exercise is completed. This means that after exercise is completed your body will continue to burn additional calories. An exercise programme will also lead to small increases in lean mass which will speed metabolism and further help you to loose weight. As part of an exercise programme for weight loss you should include a few resistance exercise in order to slightly increase lean muscle and therefore speed metabolism. The most important type of exercise for weight loss is cardiovascular (CV) exercise such as walking, jogging, cycling, swimming etc. You should look to exercise for at least three days a week (5 days a week is probably the optimum number) and should aim to burn at least 300 calories (ideally 500 but the more the better) in each session. Another consideration is the exercise intensity if you have time to do a long workout (around 60mins of CV) then keep the level fairly moderate around 70% of maximum effort you can measure this using a heart rate monitor (the formula for working out exercise heart rate zones is given below) if you only have time to do a shorter work out then aim to exercise around 80% of maximum HR. By training at a slightly higher level you will burn more calories during the workout and will raise your metabolic rate to a higher level so that you burn more calories during the post exercise period. By combining a structured exercise with a healthy eating program you will see the best results. Healthy Eating plans will appear here shortly! |
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