Weight Loss

Despite the availability of low fat foods and increasing awareness of the risks, obesity is still on the increase. However, despite the prevalence of obesity, many people do not consume enough essential nutrients to keep themselves healthy, and overweight and poor nutrition are major risk factors for some of the most common diseases in our society. These include high cholesterol levels, atherosclerosis, hypertension, heart disease, diabetes, some types of cancer, gallstones, gout, stroke, gallbladder disease, liver disease, infertility and arthritis. People who are overweight often meet with disapproval in their daily lives and may suffer psychological and social difficulties.

Hand in hand with the increase in obesity has come a national obsession with weight loss. Many overweight people are drawn to fad diets that promise fast results with minimal effort, only to see the weight go back on just as quickly once they return to their regular diet. Such a pattern of repeated weight loss and gain may contribute to lifelong obesity. The only way to lose weight and keep it off is to develop, and stick to a healthy, nutrient-dense, balanced diet and a regular exercise program.



Many people think of obesity as an excess of total body weight whereas in fact, it is excess body weight as fat. Being overweight may also be defined in terms of how someone feels about him or herself, and psychological factors play an important role in obesity and weight loss. Many people, particularly young women, think they are overweight when they may actually be underweight. For many people the optimum weight may not be as low as they would like.

An ideal or optimum weight is difficult to define. A commonly used way to assess body weight is the body mass index (usually abbreviated as BMI). A person's BMI is calculated by dividing their weight in kilograms by the square of their height in meters. A BMI within the range 20 to 25 is considered normal. A value of between 25 and 30 is considered overweight and a value over 30 is defined as obese.


Factors Contributing to Obesity

Obesity is an enormously complex problem and there are various theories as to the cause. It is likely that there are several factors contributing to the weight problem of a particular person. For years the prevailing scientific view was that in order for weight loss to occur, energy (or calories) in needed to be less than the energy (or calories) out. This usually means either eating less or exercising more, and the best results seem to happen when someone does both. However, new research suggests that weight management is more complicated than this and other factors contributing to obesity mean that a calorie is not the same for everyone. Some people seem to have higher metabolic rates and burn up food more efficiently than others. This may be due to a combination of genetic and psychological factors, gender, hormonal imbalances, poor liver function, food allergies and in some cases, medication use.


A Healthy Weight Loss Diet

While different diets suit different people, there are some general guidelines that can help people to make better food choices on a weight loss diet. A daily diet built around high levels of complex carbohydrates, low fat levels and moderate protein intake is the best approach for those wishing to lose weight. It is also important to obtain vitamins and minerals in amounts at least as high as the RDAs. A diet that consists of a wide variety of wholesome, minimally processed foods, fortified foods and, in some cases, supplements will play a part in safe, effective weight loss.



The energy value of food is measured in kilocalories, which is usually shortened to calories. The word 'calorie' comes from the Latin for 'heat' and a calorie is defined as the amount of heat needed to raise the temperature of one gram of water by 33.8 degrees Fahrenheit. The metric measurement is kilojoules. One calorie is equivalent to 4.2 kilojoules (kJ).

Food is usually defined in terms of calories as a way of comparing the relative energy value it holds. Fat, carbohydrate and protein are known as macronutrients because they provide energy. Vitamins and minerals are known as micronutrients as they have no energy value.

1 gram of fat provides 9 calories (38 kJ)

1 gram of protein provides 4 calories (17 kJ)

1 gram of carbohydrate provides 4 calories (17 kJ)



Fat is the most concentrated food source of calories and many weight loss diets are based around limiting fat. Many people trying to lose weight aim to exclude fat from their diets altogether in the belief that this will bring faster results. However, while excessive intakes of certain fats can contribute to obesity and health problems, it is important to remember that some types of fats are essential nutrients and are necessary for health.



Carbohydrate foods vary in the rate at which they are absorbed into the bloodstream. Foods high in simple sugars such as glucose and sucrose (table sugar) are quickly absorbed and this leads to a sharp rise in insulin production to move the sugar out of the blood. This is followed by a sharp drop in blood glucose and a craving for more sweet food. This contributes to obesity as these foods are high in calories. Complex carbohydrates are absorbed more slowly into the blood than simple carbohydrates, which leads to a slower insulin response. In this way, blood sugar levels tend to be more consistent, avoiding the sharp rises and falls of a diet high in simple sugars. Sucrose also seems to cause a greater increase in blood fat levels than more complex carbohydrates.

In fat tissue, insulin facilitates the storage of glucose and its conversion to fatty acids, and also slows the breakdown of fatty acids. Sharp rises in insulin may contribute to obesity and it seems that blood insulin levels correspond to body fat stores. The longer and more often insulin levels are high, the more likely sugars are to be converted to and stored as fat. Eating large amounts of foods high in both fat and sugar increases weight gain even more.

Eating too many sugar-rich foods such as cookies, cakes and candy that contain refined carbohydrates increases the risk of nutritional deficiencies as there may not be enough room for nutrient-dense foods. Sugars and refined carbohydrates require vitamins and minerals for metabolism but unlike whole grains, they do not contain enough of these vital nutrients.



No weight loss program is complete without an exercise component. When a dieter concentrates solely on food restriction to achieve results there is a loss of both body fat and muscle. This is less than ideal as muscle helps burn fat. The most effective weight loss programs involve both diet and exercise.

Aerobic exercise is the best way to lose fat. It burns extra calories, a few hundred or more per hour of exercise, depending on the type of exercise, a person's weight and how hard they exercise. Over time, exercise builds muscle which raises metabolic rate and improves the ability to burn calories and reduce fat tissue. Exercise has the added advantage of increasing metabolic rate for up to 24 hours after exercise has been completed.

More complete exercise programs also include anaerobic exercise as this is the kind which builds strength and flexibility. Strength training can also help with weight loss and improve body image and self-esteem. Building muscle mass will also increase metabolic rate, which burns more. The best fitness programs involve a balance between aerobic fitness and flexibility and strength training.


Vitamin and Minerals

Vitamin and mineral supplements can be helpful during and after weight loss as many people on weight loss diets do not consume adequate amounts of vitamins and minerals. Some common sources of nutrients such as calcium and vitamin E are found in high quantities in high calorie foods which people on weight loss diets tend to avoid.

B Vitamins

B vitamins are essential for the metabolism of food and optimal intake is necessary to ensure that this takes place effectively. Biotin and pantothenic acid supplements have been used in weight loss programs.


Extra minerals may also be useful in preventing deficiency, especially in people whose fiber intakes are high, as fiber reduces absorption of calcium, iron, zinc, copper, manganese, and molybdenum.


Since weight loss usually involves a mild process of detoxification, with the body burning fat and sometimes other tissues, antioxidants may be useful. These include beta carotene, vitamin C, vitamin E and selenium.


Limited research suggests that moderate increases in chromium, in the form of chromium picolinate, may cause weight loss, reduce fat and increase muscle mass. Because of these reports, chromium picolinate supplements have become very popular.

Researchers involved in a 1997 study assessed the effects of chromium yeast and chromium picolinate on lean body mass in 36 obese patients during and after weight reduction with a very low calorie diet. During the 26-week treatment period, subjects received either placebo or 200 mcg chromium yeast or 200 mcg chromium picolinate in a double-blind manner. After 26 weeks, chromium picolinate-supplemented patients showed increased lean body mass whereas the other treatment groups still had reduced lean body mass.1

In a 1997 study done at the University of Texas at Austin, researchers examined the effects of 400 mcg of chromium and exercise training on young, obese women. The results showed that exercise training combined with chromium nicotinate supplementation resulted in significant weight loss and lowered the insulin response to an oral glucose load.2

Essential Fatty Acids

Essential fatty acid supplements may also be useful in improving fatty acid metabolism. This is particularly important if the diet is very low in fat. Cold-pressed flaxseed oil is high in both omega-3 and omega-6 fatty acids, and is a good way to obtain these oils. Usually, three or four teaspoons a day are adequate. As cofactors that help in fatty acid metabolism, zinc, magnesium, vitamins A, C, niacin, pyridoxine, biotin, choline and carnitine may also be useful.

Other Nutrients

Other nutrients and supplements that have been used to help in weight loss include coenzyme Q10, acetyl-L-carntitine, spirulina and chitosan.


Herbs that have been used to aid in weight loss include brindleberry (Garcinia cambogia), chickweed (Stellaria media), bladderwrack (Fucus vesiculosus) and plantain (Plantago ovata).


1 Bahadori B; Wallner S; Schneider H; Wascher TC; Toplak H. Effect of chromium yeast and chromium picolinate on body composition of obese, non-diabetic patients during and after a formula diet. Acta Med Austriaca, 1997, 24:5, 185-7

2 Grant KE; Chandler RM; Castle AL; Ivy JL. Chromium and exercise training: effect on obese women. Med Sci Sports Exerc, 1997 Aug, 29:8, 992-8