Setting a goal weight is not simple. And it is never harder than in a growing child, where it is a moving target.

I have written some rather lengthy guidelines for determining ideal body weight in the pediatric patient and about what we at Kartini Clinic call “state not weight.” Today, we use the term “goal weight” rather than “ideal body weight” as “ideal” has so much baggage.

Professor Bryan Lask once asked me to participate in a debate in an international journal about whether or not complete weight restoration was necessary in the treatment of eating disorders. I was to take the “yes” view. Of course I was. Anyone who knows me knows that I regard complete weight restoration as the conditio sine qua non of healing. In plain English: you can’t get well without it.

In the setting of weight loss and anorexia nervosa, I follow my own guidelines, using their growth chart information, mid parental height, pubertal stage (this is essential), and then making an educated guess at a goal weight. But it is a guess. Then we set a meal plan that will give us 0.2 kg (0.44 lbs) weight gain a day, averaged over each week. If we do not get close to this weight gain goal, we turn up the calories. We then establish the patient’s baseline metabolic labs, such as (a minimum of ) cortisol, LH, FSH, estradiol, testosterone, glucose, insulin, leptin, Complement 3, total T3, TSH and free T4 and adjust our guess as needed.

When I evaluate a child with weight loss, I set a body weight goal as outlined above. If I am seeing the patient for excessive weight gain, however, I write something like this instead: “Setting a body weight goal in this child is not wise, given the very high starting point. It will be important to establish ordered eating at a caloric level of around 2150 kcals/day (or another number, age and activity dependent) and see what their body does with this over time. The strong family history of type two diabetes (where present) will mean we must be guided by his/her serial metabolic labs.”

We check these labs about every four weeks to monitor the patient’s metabolic return to normal with refeeding. This allows us to evaluate hormonal restoration and to see, roughly, when the brain has begun to truly believe that “the famine is over.” Metabolic labs allow us to steer by the patient’s own biology -- but there’s no doubt they make an already complex determination even more so. I guess that’s what the doctors are for. Labs (but not weights) are shared with our patients. We share everything with our parents.

Recently, I read some comments written by concerned mothers saying that their providers had set their child’s goal weight too low and would not believe them when they said that their child’s weight would need to go up in order for full psychological recovery to take place. Do we see this at Kartini Clinic?

Well, the parental responses we typically get as we set weight goals and work towards them, fall roughly into three categories: #1. “You’re the doctor, I trust your goal setting”; #2. “I don’t understand why you set her goal weight so high. I don’t think she needs to weigh this much” (this is almost invariably said about a girl); #3: “I don’t think he/she can function optimally at this goal weight you set; it’s too low. I think she/he needs a few more pounds to return to her/his good mood and energy.”

What can you say about parental response #1? “Thank you for your confidence,” I guess.

Response #2 is more common than response #3 and is more frustrating. We try to set goals using biology, not hope, belief, cosmetic prejudice or social norms. What’s important is not what Julie thinks a 14 year old Caucasian girl should weigh, for example, but what that girl’s brain and body do.

As we all swim in the sea of this culture, which values thinness above all, we get distorted messages about beauty and “normal.” And, face it: we love our children deeply and identify with them and even live vicariously through them. We bask in the reflected glory of their straight A’s, their English awards, their sports successes, their full-ride scholarships and…..their appearance. If they are thin, we feel virtuous -- as if we have raised them correctly. If they are overweight, we are blamed and  -- importantly -- we blame ourselves. So, some parents are not pleased for me to set a goal weight they feel moves their daughter out of the “slender” range.

Using their child’s growth information, pubertal stage and metabolic labs, we try to show parents how we arrived at the goal weight. In response to the common remark that “she has never weighed this much in her life,” we try to point out that she is also older than she has ever been before and that a 14 year old should not weigh what she did at 13, nor a 17 year old weigh what she did at 15. Growth means weight gain. Often, though, these cosmetically based concerns cannot be assuaged with facts.

And there is another powerful belief that makes some parents wary of “too much weight gain” -- the belief that their child will become distressed, more depressed and “worse psychologically” if they “gain too much.” There are some providers out there who share this belief as well, setting weight gain goals “their clients can accept.” The fallacy to this argument is that we are not talking about the average child or teen, we are talking about the one with anorexia nervosa.

There is quite literally no weight, however low, that will placate an eating disorder. If you set it at 120, the ED wants 115. Once you reach 115, the ED longs for 110, etc. Everyone who treats eating disorders or has a loved one with one knows this. Yet the child’s distress is so hard to bear that it is fatally tempting to think you can placate them by setting low weight goals. Low weight goals mean slow growth, linear height stunting, sub-optimal brain growth and no return/initiation of menses.

And then there’s response #3.

An inexperienced clinician is threatened by assertive parents. Old medicine sets the parents up as passive recipients of the doctor’s (or therapist’s or dietitian’s) wisdom. The new medicine makes us all collaborators in our journey towards optimal health. We come to the doctor for advice based on their training and experience -- their expertise, if you will. But parents are usually the experts in assessing their own child as a person. Enough mothers have commented that their child was not able to return to normal, happy psychological and social functioning until they were some pounds above the goal weights set for them by their team, for me, at least, to sit up and take notice. If you are interested in this, here is one mother’s story.

Dr Moshtael and I know from our experience with metabolic labs, these last few years, that it can be very hard to convince the brain that “the famine is over” and it can loosen its choke-hold on some of the hormones that can affect mood (cortisol, testosterone, estradiol, etc). The variation in this response to re-feeding probably relates to how long the patient has been ill, the age of onset, the swiftness of weight restoration, the pubertal stage at which the disease caught them and….genetics. The observation made by some parents that their child did not normalize completely until their weight was pushed somewhat higher than the initial educated guess should be respected.

After all, which is more important: some weight number or that the smile comes back?