Health implications of Weight Gain

 

Weight Gain in the form of excess body fat has implications on people mentally and physically. Mentally excess weight can cause a lowered self confidence and impact on an individuals social life. Physically excess weight can prevent an individual from partaking in the activities they enjoy. This decreases the quality of life of the individual

 

Weight Gain has implications in regards to your health and well being. With an increase in weight comes an increase in the risk of Diabetes, Heart Disease, Stroke and Arthritis. Below it is discussed how weight gain effects your longevity and disease risk and the mechanisms by which this happens. Healthy weight ranges are provided, along with ways of measuring and monitoring your progress. Throughout the article links are provided to other fitness and diet advice on how to help reduce your body weight and improve your fitness.

The Causes of Weight Gain

Weight Gain is a result of an increase in the energy consumed in relation to what is expended. The mechanisms by which this occurs can be complex, involving the endocrine system, genetics and lifestyle variables. Some of these factors are at the control of the individual and others are not. Body weight is not 100 percent modifiable, but in the majority of individuals following correct exercise and dietary advice will create significant weight reductions. Some conditions related to the thyroid and adrenal glands can result in weight gain although these conditions though are rare. Genetics can determine how easily your fitness develops and how well your body burns fat. Along with this everyone has a slightly different metabolism. Despite these factors research shows a correlation between weight gain and sedentary behaviours and physical inactivity. Studies that closely monitor dietary intake and exercise show losses in weight which correspond to the increases in exercise and decreases in food intake. (See Weight Loss, Exercise and Reduced Energy Intake ) These losses do though vary from person to person, but there is a consistant relationship between body weight gain and food intake and also a relationship between weight gain and absence of physical exercise.

 

Physical Inactivity, Diet and weight gain

 

Exercise increases the amount of energy you expend. An average 80kg adult male's resting energy expenditure or resting metabolic rate (BMR) is approximately 8500kj’s. A Tour De France athlete on a 6 hour stage will burn up to 30000kj’s during the day. One kg of body fat contains approximatley 37000kj’s. This means without large energy or food intakes these athletes will loose significant body fat due to their excessive level of exercise. This is the principle behind exercise and weight loss, if large amounts of exercise are performed a deficit in energy will cause a reduction in body weight.

Longitudinal studies show conflicting results when looking at total physical activity and body mass. This is most likely due to the differences in diet and poor reporting of physical activity levels.

A review of 22 studies using double labelled water showed those with high energy expenditures have lower body weights (1). See below diagram. Double labelled water is a method used to accurately measure energy intake and energy expenditure. The diagram below shows Non Basal Energy Expenditure (which is Exercise) and body fat percentage. The greater the level of exercise (the far right of the graph) the lower the percentage body fat.

 

The majority of studies looking at large groups of individuals draw the same conclusions. Higher physical activity levels correlate with lower weight or body fat percentages.

 

A Study of 5000 younger men and women found physical activity was inversely related to body fat levels in both genders. This means the more exercise you do the lower your body fat percentage.

The same study found that carbohydrates and fibre intakes were also correlated to lower body fat percentages. This means diets higher in carbohydrates and fibre prevented weight gain.

 

The above research is supported by two other smaller studies reporting similar results in which higher fat intakes were observed in overweight individuals along with lower levels of exercise (2,3).

 

It should be noted that these 3 studies are longitudinal studies, not control trials. This means the participants are researched over time in their free living environment. These studies show support to higher carbohydrate intakes along with higher amounts of physical activity causing weight loss. The simplified argument for this is that high fat diets tend to be both dense in energy which results in an overall larger intake of food. High physical activity levels similary create a energy deficit by burning large portions of energy resulting in an overall decrease in weight.

 

Risks Associated with Weight Gain

Weight gain is a risk factor for diseases such as heart disease and diabetes. The risk of developing these diseases increases exponentially as the weight of the individual increases. Type 2 Diabetes has been shown to shorten life expectancy and lead to other health complications. See article on Exercise and Type 2 Diabetes.

Weight Gain is associated with elevated blood pressure (4) which places the heart under a constant higher work load.

A review of 6 well known longitudinal studies, these are studies examining the onset of a condition over time, showed the risk of mortality (death) increased with increasing body weight. The increased risk was found in individuals with a BMI above 27 and increased with increasing weight up to the highest BMI (5). The risk increase was exponential, meaning the more overweight the individual the greater the effect that weight has on their health.

One of the 6 longitudinal studies was the American Cancer Prevention study containing 1 million people. The below graphic is a visual representation of the risk of weight gain. As mentioned above the risk increases steadily from a BMI of 26-27, before sharply increasing at higher BMI’s (6).

Healthy Weight and Body Fat ranges

Knowing that excess body weight is detrimental to an individual’s health what is the recommended healthy weight range. A combination of 2 measures is recommended to access body weight. The first measure is BMI which measures body density; the second measure is waist girth or circumference which measures abdominal fat. 

 

Typically Body Mass Index (BMI) is used as a measure of body fatness. This is due to the ease of measurement. BMI is actually a measure of body density. An individual with a high amount of fat will have a higher body density. One of the problems with BMI is that muscle weight is not taken into consideration. So a BMI of 25 for a weight trained individual might be equivalent to BMI of 22 for an individual with a lower muscle mass. Despite this BMI is a good measure of health risk associated with excess weight.

 

Combining BMI with waist girth measures is a better evaluation of body fatness. A waist girth measure is an indicator of abdominal body fat which is a risk to your health. For this reason checking your BMI and your waist girth will provide a better picture of your current health

 

In order to measure your BMI you will require a tape measure and a set of scales

Measure your height in Meters and weight in kilograms.

 

 

The equation is as follows BMI = Weight/(Height2)

 

 

For a 180cm male weighing 78kg this would be 78/(1.8*1.8) = 24.07

 

 

To Measure your waist girth take a tape measure place it around your waist at the level of your navel (Bellybutton). On a normal breath out, record the reading, remove the tape and repeat to ensure the tape was the same height at the back and the front as this will affect the reading.

 

 

***Recommended waist circumferences will differ with differing population groups. An Asian demographic will require a lower value due to a difference in body shape. Like with the BMI no measure is perfect. You need to use common sense in evaluating your weight.