Weight Control

Introduction.

Losing weight is a common ambition. However it is really fat that most people want to lose. A lot of people want to lose fat from specific areas and there are good reasons for this.
  1. Excess fat in the trunk region is close to our vital organs and is associated with increased levels of heart disease, some cancers and other inflammatory chronic diseases.
  2. Fat in other regions, while not so bad for health slows people down and reduces mobility. For athletes this means you are slower. For the more elderly this contributes to immobility and dangers from falling over.
  3. Where a person loses fat from first is determined primarily by genetics so toning abs will not reduce abdominal fat any faster than upper arm fat. 

How to lose fat most effectively. 

Control Appetite

Appetite is ultimately controlled by the brain. A section called the hypothalamus is a key centre of control. It releases neuropeptides (NPY, AgRP and POMC) that control our hunger. NPY and AgRP increase hunger and POMC diminishes it. However these are not the only factors that need to be considered to understand appetite.
1)       Exert willpower. We can overide the impulses caused by neuropeptides by using our willpower.
2)       Sleep over 8 hours per night. Sleep restriction leads to increased food intake. Lack of sleep raises levels of the appetite stimulating hormone, ghrelin and suppresses the appetite suppressing hormone, leptin. Ghrelin causes the hypothalamus to release the NPY and ARP neuropeptides that stimulate appetite. Leptin reduces the release of NPY and ARP from the hypothalamus, and increases inhibitory POMC neuropeptides. Think of ghrelin as “gremlins” that increase appetite and leptin as your weight control friend.
3)       Reduce the glycaemic load of your diet. Carbohydrates stimulate appetite between meals and dampen appetite after meals. There are blood sugar sensors in the hypothalamus that will release the hunger creating NPY and ARP neuropeptides between meals and the hunger reducing POMC after meals. However carbohydrates also affect appetite when insulin is released in response to absorption of carbohydrates. Insulin, like leptin, dampens appetite by reducing NPY and ARP and increasing POMC neuropeptides. The effect of carbohydrates on appetite will depend on the relative sizes of the insulin effect and hypothalamic blood sugar sensors effect. In practice it is best to get out of the habit of eating carbohydrates to satisfy your hunger between meals as this most likely leads to more hunger from NPY and ARP neuropeptides and less effect from insulin as the amount eaten is not that great.
4)       Proteins sate appetite. They also stimulate insulin release, which dampens appetite. However protein intake is not correlated with any change in insulin response for most types of obese subject, so protein’s appetite suppression may relate more to non-insulin effects.
5)       Fats seem to be able to inhibit appetite through a mechanism found in the hypothalamus.
6)       Illness often reduces appetite, and this is due to chemicals such as TNF-a, IL-1 and IL-6 which are released during illness.
7)       Appetite suppressants are a class of drugs that generally are dangerous for unsupervised use. Problems associated with their use include pulmonary hypertension, heart valve damage and haemorrhagic stroke. Natural appetite suppressants may be OK. The most commonly used ones are based on green tea or fucoxanthin extracted from seaweed.
8)       Appetite stimulants should be avoided by those trying to lose weight. These include artificial sweeteners and monosodium glutamate E621.
 

Low GI diets

A low GI approach to weight loss is probably the most effective strategy as this leads to a reduction in insulin levels which is the hormone most closely associated with fat deposition around the body.
Low GI diets are also beneficial for blood sugar levels and blood lipid profiles such as cholesterol and triglyceride levels.
 

Rate of weight loss

1)       Faster rates of weight loss perform better than slower ones. For example rates greater than 1lb a week were more effective in studies than rates slower than 1lb per week.
2)       However faster rates of weight loss could lead to muscle wastage.
3)       Faster weight loss could also lead to greater rates of release of toxins from adipose tissues.
 

Exercise

1)       Resistance exercise leads to more muscle mass and an increased metabolic rate making it easier to burn calories. ** muscle tissue requires more calories at rest than adipose tissue.
2)       Cardiovascular exercise has health and psychological benefits, however it is generally ineffective at causing weight loss unless it is intensive in nature. As a rough guide if you are breathing comfortably then your exercise needs to last over 1 hour to have any sort of effect on weight loss. If you are breathing heavily during your exercise then you can expect more weight loss as a result of exercise.
3)       The effects of cardiovascular exercise on people vary. Some are “responders” and others “non-responders”. Non-responders are thought to be people who reduce their levels of everyday activity when undertaking an exercise program, in order to compensate. In other words if you are going to treat yourself with extra food or slump in front of the TV after introducing a new exercise routine then it may well not have any effect on your weight.
4)       Most studies show that exercise is more effective for weight loss for males than females.
 

Measuring progress

  1. BMI is body mass index. It is calculated as weight in kg divided by height in metres squared (kg/m2). This is the most commonly used measure, but it is not the best as it does not give any indication of where fat is stored. In health terms visceral fat (fat around the organs) is much worse than subcutaneous fat (fat under the skin).
  2. Body fat measurement devices using electrical impedance are another commonly used method. They can be a) handheld, b) like bathroom scales or c) use electrodes attached to both hands and feet. They look good on the face of it. However most devices make large adjustments for age and sex that make the measurements meaningless. I don't recommend you take any figures you get from these devices seriously. Their only use is in comparing changes while you keep your sex, age and height at the same level.
  3. Body fat measurement by skinfold calipers. 3 or 7-point measurement via skinfold calipers is more accurate than using electrical impedance devices. Make sure you understand what formula is being used to come up with your final fat percentage figure. Any fudge factors based on age or sex need to be viewed with some skepticism.
  4. Waist measurement in centimetres is a good approach, as this indicates where any unhealthy fat is being stored.
  5. A height to waist ratio is also a useful measure, and gives an idea of risk of diseases such as heart disease and diabetes. It is best to keep the ratio above 2. So say you are 6ft (72inches) tall then your waist should be less than 36inches in circumference.

Calorie counting / Diet restriction

1)       Diet restriction can cause raised levels of stress, especially if counting the calories. This leads to greater levels of the stress hormone cortisol, which causes weight gain the in abdominal area.
2)       Calorie counting often leads to a move towards a higher carbohydrate diet in order to remove high calorie fats for the diet. Fats contain 9 kcals/gram against carbohydrates 4 kcals/gram. However higher carbohydrate diets are associated with weight gain as they lead to more insulin release and insulin is the hormone which encourages fat to be stored around the body.
3)       Calorie restriction slows the metabolism. The body responds to the apparent starvation by conserving its resources. This makes it harder to lose weight. It also increases hunger and leads to a reduction in activity levels, both of which make losing weight more difficult.
4)       Many low calorie foods are not that healthy. Examples include the artificial sweeteners, some of which are associated with an increased risk of cancer, while most increase appetite, making it harder to diet successfully.
 

Calorie burning / How many calories can I burn?

It is difficult to find good quality advice when you seek to find out how many calories can be burnt during exercise. The problem is that most people generalise too much, as the calculation of how many calories a person can burn is very complex. In fact it is impossible to determine. Approximations are dependent on a good knowledge of biochemistry and this is rarely displayed in either sports nutrition books or from online resources. Below I list some of the misleading calorie burning information that it is easy to come across.
1)       Tables showing how many calories are burnt doing different types of exercise such as swimming, running, badminton, walking etc. These are never going to be accurate as even when they include a persons weight they don't ever take into account the intensity of the exercise and the fitness of the person. Some of them imply that at a certain speed you will burn more calories. This is very misleading as for one person they may be at their limit to reach that speed whereas another my be taking it easy at the same speed. The person who is at their limit will be burning appreciably more calories as anaerobic exercise burns fuel approximately 15 times as fast as easy aerobic exercise.
2)       Gym machines and sports watches. Sorry, if you just paid lots of money for a new gizmo or gym membership and thought you’d learn how many calories you’d be burning, you won’t. The calculations they all use are based on approximations that cannot relate to real life variability in the person who is using them. As pointed out in point one, the fitness of an individual is a key component. Others that are rarely considered are environmental conditions. For some people running in hot conditions will cause them to reach their limits sooner, however this won’t be the case for everyone.
OK, so you want to know how you can burn more calories. Here are some ideas.
1)       Include hard exercise for a portion of your workout. You accelerate the amount you burn by doing this and if the effort stimulates your anaerobic metabolism the calories burnt will be many times higher.
2)       Extend the duration of your workouts. Simple maths shows that at a given rate of burning calories you will burn more if you exercise for longer.
3)       Vary your exercise regimes. The body automatically tries to become efficient in performing the exercise you practice. By giving yourself new exercises to do it challenges your body and you will end up burning more calories. .
 

Fructose

Fructose is known as fruit sugar. It has a reputation as a healthy alternative to table sugar, however things are a bit more complex than this suggests. Firstly fructose makes up part of table sugar. The other part of table sugar is glucose. Secondly fructose is 1.73 times sweeter than sugar, although this is in its unheated form. When heated it is roughly the same sweetness as sugar.
1)       Fructose can lead to fat deposition if taken in excess.
2)       When consumed in moderation it actually improves sugar processing by the body.
 
In a nutshell
To control weight make sure you are not eating too many carbohydrates unless you are exercising a lot. Remember that using exercise to lose weight will be increasingly effective the more time and effort you put in.

 

Don't miss.... more from Robin.

  • Calories are the foundation of many diet plans, however there are a number of reasons to be cautious about starting a calorie controlled diet.
  • Here are 10 weight loss tips for 2012. I've ordered them in what I think are their importance for most people.

  • Do you want to know how to lose weight and keep it off? Many people do, but not many people really know what is the best way of going about it. There are many diets out there, but most are not very effective for most people. The low GI diet, described in this article is one of the most effective ways of controlling your weight.
  • Just how effective is exercise when it comes to weight control?