Expectations & best weight

You will learn why weight loss naturally slows down and eventually plateaus in any weight loss effort or intervention. The reason is biological — when your brain detects fat loss, it raises appetite and lowers metabolic rate to defend against further loss.

You will be invited to consider the point at which weight loss plateaus as your BEST WEIGHT — the weight you arrive at when living your healthiest, most enjoyable lifestyle, at an effort level you can sustain.

You work on finding your healthiest, most enjoyable, and sustainable lifestyle — and then your brain and body will tell you where that lifestyle lands you. That is your best weight.

How much weight will I lose? How much weight should I lose? I was told I should lose 40 pounds. I want to fit into my clothes. I know when I was a certain weight I felt great.

What are your thoughts about your weight loss expectations? Many people beginning a weight management effort have thoughts about a target or goal weight, and thoughts about what would be their ideal weight.

Weight is not a behaviour

Would you be surprised to know that your weight is considered something you do not have control over? Put simply, weight is not a behaviour. It is not something you do.

Consider for a moment the things that affect your weight that you do have control and influence over. When you are eating as healthily and moderately as you can while still enjoying your life in a sustainable way, and when you are as active as you can be in a sustainable way, exactly where you land with your weight is determined by an appetite system that is hundreds of thousands of years old.

Another name for your appetite system is your weight regulation system. It comprises three levels of your brain. As you lose weight, the fat loss is expertly recognized by the GateKeeper in your hypothalamus — the homeostatic system. In response to weight loss, the GateKeeper initiates changes that favour weight regain: your metabolic rate decreases, and wanting via the GoGetter increases as your motivation system is strengthened. These changes are the reason for the characteristic shape of all successful weight loss efforts.

The shape of human weight loss

This shape is so characteristic of almost all weight loss patterns that you could think of the graph below as the shape of human weight loss.

In a landmark review paper1, Kevin Hall and Scott Kahan describe this process. The shape of the graph above represents a steady behavioural battle against a biological response that progressively opposes weight loss. All of this data is the product of validated mathematical models of energy expenditure applied to real weight loss in real humans, with accurate gold-standard metabolic rate measurement. While weight and metabolic rate are measured directly, energy intake, appetite, and effort are estimated.

A worked example

To explain why the shape of weight loss looks like this, the researchers used the example of a hypothetical 90-kg woman who loses weight and keeps it off. The weight loss she experiences is represented by the graph below. Note that her weight loss plateaus at approximately six to nine months.

Before her weight loss effort, this hypothetical 90-kg woman was consuming an average of 2,600 calories per day and burning an average of 2,600 calories. She was consuming what she was burning, and her weight was stable.

The weight loss process begins with her dropping calorie intake from 2,600 down to 1,800 kcal per day, establishing an 800-calorie-per-day deficit. This is the change that initiates her weight loss.

What happens to metabolic rate

The next graph suggests what happens as her metabolic rate slows in response to her calorie deficit and subsequent fat loss. It drops from 2,600 kcal per day to roughly 2,400 kcal per day within the first month, followed by a stabilization. This is how the GateKeeper drops metabolic rate in defence against fat loss.

What happens to calorie intake

What about calories in? This is important. Increases in calories consumed are considered the most important determinant of the slowing and eventual plateauing of weight loss — and of this characteristic graph shape. Look what happens to her energy intake. She starts at 1,800 calories a day, but as soon as she starts losing, she is immediately consuming more. By three months she is — often unwittingly — consuming an average of 2,200 kcal per day, a full 400 calories more per day than when she started. By six to nine months she is consuming an average of 2,400 calories per day.

So you can see why at six to nine months her weight is plateauing. She is consuming 2,400 kcal per day and her metabolic rate is 2,400 kcal per day. She is consuming what she is burning, and her weight loss has stopped.

What is driving her to eat more

The next curve is very telling. This is the answer to why this woman was driven to eat more as soon as she started to lose weight. This graph shows the actual changes in her appetite — defined here as the number of calories her brain would prefer her to be eating each day to regain the weight she lost. In response to weight loss, appetite — and therefore intake — immediately increases. Think of this as the GateKeeper recognizing fat loss and making the GoGetter (appetite) work harder.

What this means for effort

What follows may seem confusing, but it is worth understanding because this is what is actually happening.

At first our hypothetical woman was eating 1,800 kcal per day, and her appetite was asking for 2,600 kcal per day. Her effort was that of eating 800 kcal less each day than her brain would prefer. By three months in, her appetite is at 3,000 kcal per day, and she is eating an average of 2,200 kcal per day — meaning her effort at three months is the same as at the beginning: 800 kcal less than her brain is asking for. (But because she is eating more, her weight loss is already slowing.) At six to nine months, her brain is asking for 3,200 kcal per day while she is eating 2,400 kcal per day. Again her effort is the same: 800 kcal less than her appetite is dictating. At this point, though, because she is eating 2,400 kcal per day on average, her weight loss has plateaued.

This final graph demonstrates the point of adherence to effort. To sustain weight loss calls for a sustained effort. The effort level is defined as taking in 800 calories less than your brain desires, long into the future.

Best weight, defined

So now you see that when you are beginning a behavioural weight loss program, it is suggested that you consider establishing a level of effort that is sustainable over the long term.

When you are doing the best you can, at an effort level you can maintain, exactly where your weight lands is determined by the response to weight loss within you — your appetite system, which regulates appetite and metabolic rate. This is what it means when it is said that you do not control your weight. You control, at best, your behaviours and effort. When you are doing the best you can do, your weight lands at a BEST WEIGHT. Someone losing weight and keeping it off is practicing the same level of effort long into the future.

You now understand that often, at around six to nine months after beginning to lose weight, calorie intake will increase to the point where the number of calories consumed matches the number of calories burned. When this happens, weight loss stops, defining the characteristic weight loss plateau.

In this scenario, you work on finding your most modest, yet enjoyable, and sustainable lifestyle — and then you stand back and let your brain and body tell you where your best effort lands you.

You work on finding your healthiest, most enjoyable, and sustainable lifestyle — and then your brain and body will tell you where that lifestyle lands you.

In this scenario there are two competing processes: your brain defends your former weight, while you defend your best weight. Many people at this point will ask: does the brain ever give up trying to return you to your original higher weight? Does it ever let up eventually? After all, does it not prefer you to be at a healthier weight? Unfortunately, at this point we have no evidence of the brain letting up — in either increased appetite or decreased metabolic rate.

You will read repeatedly in this material that overweight and obesity is a real medical condition that is primarily genetically conferred, progressive, and centred in the brain. These concepts are very well illustrated here. Genetics determines the degree to which your brain defends against weight loss — the degree of increased appetite, and the degree of decreased metabolic rate. Your weight loss results will necessarily be unique to you. All the graphs above from the Kevin Hall review paper are taken from an average of thousands of subjects. Your results can be very different in either direction. This is why the concept of a predetermined target weight, ideal weight, or goal weight makes no sense at all.

Behavioural best weight, and behavioural-plus-medication best weight

This is an important point. If you are engaged exclusively in a comprehensive behavioural weight management program and you reach a plateau, further weight loss is possible and probable. It is extremely common — and will continue to become even more common — to see a behavioural program combined with an obesity medication. Obesity medications can be very effective at creating a lower best weight.

The graph below is from the SCALE Maintenance Study2. After 12 weeks of losing weight with a diet, subjects were randomized to either a placebo or an obesity medication. The two subsequent weight loss curves are the same shape — but the weight loss in the medication group is deeper.

You will remember that appetite and weight are regulated in parts of the brain — the GateKeeper and the GoGetter — that you do not have access to, but obesity medications do. You can think of the effect of obesity medications as dampening the brain's "weight-gain-favouring" response to weight loss. The GateKeeper becomes less alarmed by fat losses, and the GoGetter becomes less sensitive to cues. Wanting decreases.

If further weight loss would improve health and quality of life, and yet you believe that you cannot realistically eat less at a sustainable effort, the addition of an obesity medication can be tremendously sensible. Currently, several obesity medications are available, safe, and effective. The average percentage of body weight loss achieved with these medications is advancing significantly. Obesity medication should be an option for anyone who qualifies and is interested.

The health benefits of weight loss happen earlier than you think

A sustained weight loss of as little as 5–15% of body weight results in clinically significant health benefits. These benefits include substantial reductions in deaths from heart disease and stroke, reductions in heart disease risk factors (high blood pressure and high cholesterol), improvement or remission of diabetes, and improvements in conditions such as sleep apnea, fatty liver, and osteoarthritis. A 5–15% body weight loss also importantly results in significant improvements in health-related quality of life. Larger percentages of weight loss have been shown to reduce the risks of a series of 11 cancers.

Will losing weight make me feel better about my body?

A common goal of weight loss is to feel better about how one looks. A common expectation is that weight loss always results in improved body satisfaction, and that the more weight that is lost, the happier one will feel. Would you be surprised to know that this is regularly untrue?

Simply put, how you feel about yourself can be inconsistent with how you look. Many people who are thin or of average weight dislike their appearance, or are dissatisfied with certain parts of their body. Many people who are heavy feel attractive and comfortable with their appearance.

The subject of body dissatisfaction, and the work involved in addressing it, is covered more fully in the Resilience module. Briefly: body satisfaction is more about the beliefs you hold about your body than it is about the size of your body. These beliefs are shaped primarily by external messages received about body shape — from a weight-obsessed culture, from family, coaches, and friends. Body satisfaction is about being more accepting and less critical of how you look. Those who have or achieve body satisfaction will describe that some aspects of their appearance they like and some they tolerate — but most importantly, they spend minimal time focused on their image, and are freer to focus on other things.

Read more in the Resilience module →