Weight management is the phrase used to describe both the techniques and underlying physiological processes that contribute to a person’s ability to attain and maintain a certain weight.
Most weight management techniques encompass long-term lifestyle strategies that promote healthy eating and daily physical activity.
Moreover, weight management involves developing meaningful ways to track weight over time and to identify ideal body weights for different individuals.
Due to the rising obesity rates in many parts of the world, proper weight management strategies most often focus on achieving healthy weights through slow but steady weight loss, followed by maintenance of an ideal body weight over time.
Rising obesity rates are a major concern around the world, especially in North America. About 60% of Americans and Canadians are either overweight or obese.
Understanding the basic science of weight management and some of the strategies for attaining and maintaining a healthy weight is very important to a person’s overall health because obesity is a risk factor for many chronic diseases, like Type 2 diabetes, hypertension and cardiovascular disease.
There are many factors that contribute to a person’s weight, including: diet, physical activity, genetics, environmental factors, medications, and illnesses.
Each of these factors affect weight in different ways and to varying degrees, but health professionals most often stress the importance of diet and physical activity above all other factors because they can be affected by conscious behavior modification.
The following is a review of some of the key components of weight management in humans.
The science behind weight management is complex, but one of the key concepts that governs weight management is Energy Balance.
Energy Balance is the phrase used to describe the difference between the number of calories a person consumes and the number of calories that same person expends (a.k.a. burns) in a given time period.
There are three possible scenarios when it comes to the energy balance equation:
Outcome: Weight remains unchanged Calories consumed > Calories expended Also known as Positive Energy Balance
Outcome: Weight increases
Calories consumed < Calories expended Also known as Negative Energy Balance
Outcome: Weight decreases
The calories a person consumes come from both the foods and drinks they eat and drink. The calories a person expends comes from their basal metabolic rate and their daily physical activity.
When eating a healthy diet mainly composed of vegetables, lean meats, and fruits, the human body is very good at maintaining a neutral energy balance so that calories consumed do not substantially exceed calories expended in a given time period and vice versa.
This energy balance is regulated by hormones like Leptin (suppresses), Ghrelin (stimulates), and Cholecystokinin (suppresses) which either suppress or stimulate appetite.
This unconscious regulation of energy balance is one of the factors that make sustained weight loss very difficult for many people.
That being said, consuming fewer calories than the numbers of calories expended each day is fundamental to weight loss in both the short and long term.
If attempting to lose weight, the National Heart, Lung, and Blood Institute (NHLBI) recommends a slow and steady approach by eating 500 fewer calories than the number of calories burned or expended each day.