THE G.I. FACTOR AND WEIGHT REDUCTION: THE NEED FOR EXERCISE
A ‘fast metabolism’ is not necessarily a matter of luck. Exercise, or any physical activity, speeds up our metabolic rate. By increasing our kilo-joule expenditure, exercise helps to balance our sometimes excessive kilojoule intake from food.
Exercise also makes our muscles better at using fat as a source of fuel. By improving the way insulin works, exercise increases the amount of fat we burn. A low G.I. diet has the same effect. Low G.L foods reduce the amount of insulin we need which makes fat easier to burn and harder to store. Since body fat is what you want to get rid of when you lose weight, exercise in combination with a low G.L diet makes a lot of sense!
Why exercise keeps you moving. The effect of exercise doesn’t stop when you stop moving. People who exercise have higher metabolic rates and their bodies bum more kilojoules per minute even when they are asleep!
The body loves to store fat. It is a way of protecting us in case of famine. In the midst of plenty we are building up our fat stores.
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FAT LOSS: COUNTERACTING ENERGY SPARING ADAPTATIONS
The loss of body fat can lead to a range of physiological outcomes which, in turn, affect the further loss of body fat. Physiological adaptation to weight and fat loss can be divided into predictable changes (such as the decline in RMR in response to the loss of lean mass) and adaptive changes (where the body actively works to reduce the rate of weight loss). Dr Rudy Leibel and his colleagues from Rockefeller University in New York have tried to quantify the adaptive changes in lean and obese people as they lose weight. For a 10 per cent weight loss, they found that total energy expenditure declined by about 450kcal, of which about half could be explained by the changes in body composition and half could be considered adaptive.
The main way of counteracting the adaptive reductions in energy expenditure is through physical activity. This has been shown in several studies to counteract the energy sparing effects of dietary restriction. It does this by increasing energy expenditure both during and after exercise and by maintaining lean body mass. Studies examining exercise, however, have not always been convincing, possibly due to the difficulty in getting people to comply with the exercise regimens that have been set for them. There is still enough evidence to suggest that exercise can help with those who do comply and indeed may be the most effective form of continuing fat loss in the maintenance stage. There is little argument amongst scientists that diet appears to have the most immediate effect on fat loss, but it is now also becoming increasingly clear that exercise should be the mainstay in any fat loss maintenance program
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THE FATE OF FAT IN FOOD
Fatty acid molecules travel through the blood as either FFAs or as triglycerides OTGs) which is a group of three fatty acid chains joined by a glycerol molecule. An analogy may be footballers
roaming the streets on their own, or joined by a team manager. Triglycerides cannot get directly into the fat cell because their molecules are too big, so the team needs to be broken down into FFAs and glycerol units like the footballers having to pass single file through the door into a nightclub. Once inside the nightclub (fat cell), they join up with the glycerol into a ‘team’ again and are stored as TGs.
Keeping the nightclub analogy, our footballers have to get past a doorman. In the fat cell, the main ‘doorman’ is the hormone insulin, which is formed in the pancreas and secreted into the bloodstream in response to a rise in blood sugars. Before a meal (low insulin), the doorman has the exit open allowing FFAs to leave to supply energy for the body. After a meal (high insulin), the doorman closes the exit and opens the entrance to allow FFAs to enter. Insulin also activates an enzyme, lipoprotein lipase (LPL) in the fat cell. This acts like a ’spruiker’ outside the nightclub touting for business. Adipose lipoprotein lipase (ALPL) breaks FFAs off the TG so that they can enter the fat cell.
Insulin also acts as a doorman for the muscle cell but here the functions are somewhat different because he has two entrances to control. Before a meal he has the ‘fat door” open to allow FFAs into the muscle cell to provide it with energy. He also activates muscle LPL which breaks down the TG teams passing by to allow FFAs to get through the door. After a meal, he closes the fat door and opens the ‘glucose door’ so the muscle switches from running on fat to running on glucose. (Interestingly, if the muscle needs a lot of energy such as during exercise, the glucose goes straight in through another door that insulin has no control over.)
Basically, when the body needs more energy than is currently available from food, triglycerides in the fat pool are broken down into FFAs plus glycerol and sent to the muscle via the bloodstream to help out. It’s as if someone has run into our ‘nightclub’ and called all the footballers out to help out in another building down the road. The process is triggered by another enzyme which, like all enzymes, causes a reaction but doesn’t take part in that reaction. Hormone Sensitive Lipase (HSL) is the enzyme involved in this removal of fats from the fat pool. It does
so under orders from a range of chemical ‘alarmists’ in the bloodstream, particularly the catecholamines, or hormones secreted from the adrenal glands at the top of the kidneys. The catecholamines, therefore, facilitate lipolysis, but inhibit lipogenesis. Insulin, on the other hand, facilitates lipogenesis, but inhibits lipolysis.
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BABY AND CHILDHOOD INFECTIOUS DISEASES: POLIOMYELITIS
The prevention of poliomyelitis, commonly known as polio, is the conquest of the current quarter of a century. Once a disastrous and diabolical disease with a high mortality rate, and an even higher harbinger of partially paralysed bodies, it is now seldom seen in the acute stage. Until the mid-1950s it regularly left a trail of wreckage and havoc on the Australian population, and in fact in all Western countries, to say nothing of the appalling disasters it wrought in the developing lands.
But in the mid-1950s, all that changed. The sudden development of a suitable and highly effective vaccine by Dr Salk, and mass immunization campaigns, brought the disease to a sudden halt. Since then, Salk injections have been largely replaced by Sabin oral vaccine, and this is currently recommended for all babies from the age of two months. The death rate from polio plummeted, and the figure has been zero for several years now.
But it will remain this way only as long as parents are vigilant and continue to have their infants immunized along the recommended lines. Polio is still as rampant as ever in the Third World, which is not very far from Australia’s shores. If our national immunization rates fall, then polio could rapidly make a come back in Australia. It is perfectly feasible that it could even return to the pre-vaccination days and again become a major killer and paralyser. It is unlikely that, if the present trend for vaccination against polio continues, many doctors (or anybody for that matter) will witness a case of polio during their lifetime. However, it is worth knowing the symptoms, if only to alert parents to the horrid consequences if they happen to become careless in not arranging for a child to receive the proper course of immunization.
Early symptoms are often vague. They may simulate an oncoming bout of the flu, and the patient may seem to recover temporarily. But a recurrence of fever, backache, neck stiffness, nausea and vomiting may supervene. This may ’smoulder’ for several days, perhaps up to a week.
Then suddenly the major symptom occurs: paralysis. It may accompany the fever. It is often very variable, ranging from minor weakness of a single muscle group, to severe debilitating loss of function of any section of the body. The most important is the respiratory system; if this is affected, death may be imminent unless immediate emergency facilities are available. These entail the use of an artificial respirator, and its use for an ongoing period of time may be essential to maintain life.
Treatment
Symptoms such as those mentioned above, occurring in an unvaccinated child, require the urgent attention of the doctor. Prompt treatment may be essential to preserve life, especially if the breathing mechanism is affected. Treatment must be carried out in hospitals where the attention of experts is available and full facilities aimed at preserving life are available. This is no game for amateurs or do-it-yourself methods at home.
Younger generations of parents have only heard about polio. With the passage of time and the paucity of cases heard about, stories of the disastrous consequences of yesteryear often fall on deaf ears. And as the likelihood of contracting polio seems minimal there is a general tendency for young people to be complacent. ‘It can’t happen to me or to my child. It’s history … old hat… something in granny’s day.’ All too often apathy can set in. Do not be lulled into a false sense of security and neglect to have your babies immunized against this potential killer. It is simply not worth the risk.
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THE FIRST MONTH
Activity
Baby actively thrusts arms and legs about willy nilly in a playful attitude. Movements of the arms, hands and legs are largely reflex actions. For example, when you rub your finger gently over the baby’s palm you will notice how the baby will automatically, reflexively grasp it with curled fingers. If the baby’s head is unsupported, it will flop backwards and forwards loosely. If left lying on the abdomen, the baby will try to lift the head or turn it to one side so that breathing is not obstructed. Supported in a sitting position, the baby may try to hold the head in line with the body for brief periods of time. Fingers are quite often kept clenched. If an effort is made to keep them open, the baby will automatically tend to close them. The baby may hold an object for a short time but generally drops it after a few seconds. There is a tendency to stare at things, but no effort made to reach out and grab them. The two eyes tend to be co-ordinated in their movements.
Talk
The baby tends to cry a good deal, this being a method of gaining attention as well as filling the lungs with oxygen. The baby also makes little noises in the throat. If spoken to, he or she tends to respond.
Mind
The 1-month-old baby prefers to sleep most of the time, being attentive for only about ten per cent of the time. There is little facial expression, and the baby tends to give a vague stare during waking hours. He or she seems to prefer patterns to look at, rather than be attracted by colour or brightness or size of objects; familiar objects, such as parents, tend to give a little excitement. However, at this age the baby cannot concentrate on any single object for long, tending only to pick it up automatically if it comes into the range of vision but readily letting it. slip out of view without making an effort to retain it—when a person walks past, for example. The baby tends to look up and down at objects, or from one side towards the centre of the line of vision. If objects reappear within a few seconds the baby may remember them.
The baby becomes alert to the value of crying for attention, likes receiving attention, and will tend to stop crying if held and cuddled, or if seeing familiar faces, such as mother’s. Reflexes tend to become more efficient and effective.
Relationships
The baby dislikes pain and will let you know about it by crying. He also responds to comforting, and ceasing crying quickly indicates the desire to be comforted when in distress. Occasionally the baby will react to a smiling face, and may return the smile; a familiar voice may also bring a response. The baby will tend to look at mother’s face, looking intently into her eyes, and if obviously distressed may quieten down. The response to changing a wet nappy is often remarkable.
Baby tends to adjust to the person holding him or her, to mould to the body for a more comfortable union; the little one may pluck at the person, curling fingers reflexively around parts of their body such as their fingers. During feeding the baby may suckle noisily, grasping at the breast and nipple actively.
There may be obvious recognition of parents’ voices, but for the most part there is a vagueness about the baby’s stares. He or she may lie impassively for many hours, and when awake tend to stare into space without obviously concentrating on anything. The baby tends to sleep, wake up, cry, make little noises and eat, in a very disorganized manner.
At this age, the baby likes to have two feeds at night and five or six during the day. There are two to four bowel actions each day.
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