WLS NEWS: Why Did They Lose More Weight Than Me?”

[Guest guest]

Why Did They Lose More Weight Than Me? " - by K. Buffington,

Ph.D.

During a recent support group meeting, five patients whose surgical

procedures were identical and performed on the same day asked why

they were losing weight at different rates. Three months following

laparoscopic adjustable gastric banding, the only male patient,

, had lost 71 pounds. , on the other hand, had lost 57

pounds, Sally had lost 40 pounds, Sue was 29 pounds lighter, and

had lost only 19 pounds.

Why had lost more weight than the female patients? Why had

Sue and experienced less weight loss than the other

patients? Were and Sue not adhering to the recommended

postoperative dietary protocol? Were they consuming calorie-dense

beverages or foods, such as milkshakes, colas, cake, ice cream? Did

and , who lost the greatest amounts of weight, exercise

more regularly than Sally, Sue, and ?

In order to determine why there were such large differences in

weight loss between patients, we examined the lab results,

nutritional profiles, and clinical reports of their most recent

follow-up appointments, which had taken place only 3 and 4 days

earlier.

To attempt to understand why some individuals lost more weight than

others, we first examined body size measurements before and after

surgery. All patients had a somewhat similar body mass index (BMI)

prior to surgery, i.e. range 43 to 47, but patients differed as to

where on their bodies fat was distributed.

Body fat distribution is determined by measuring the circumference

(distance around) the waist and the circumference of the hips and

then dividing the waist circumference by that of the hips to derive

the waist-to-hip ratio (WHR). A male with a WHR greater than 0.95

stores much of his body fat around the waist (abdominal fat).

Premenopausal females store fat in their hips and buttocks and

generally have a WHR less than 0.80, but females with a WHR greater

than 0.80 tend to store fat in abdominal regions, as well.

Deep abdominal or visceral fat has a much faster rate of turnover

than fat that is deposited on the hips and thighs. For this reason,

larger amounts of abdominal visceral fat are lost with calorie

restriction than are fat deposits on the hips and thighs. A person

with abdominal obesity, therefore, is likely to lose weight more

rapidly on a diet or after surgery than would someone with fat on

the hips and thighs.

Men tend to store much larger amounts of fat in abdominal visceral

adipose depots than females and, for this reason, men are generally

able to lose weight more rapidly than females. had a pre-

surgery WHR of 1.2 and at 3 months had lost most of his weight from

around his waist. The greater rate of turnover of ' abdominal

fat is likely to be one of the primary reasons he was capable of

losing more weight than the female patients.

, Sally and Sue all had similar WHR, i.e. 0.85, 0.84, and 0.83,

respectively. Changes in waist and hip circumferences at 3 months

after surgery were also similar, with all patients having a

proportionately greater loss of inches from the waist than from the

hips and thighs.

who had lost the least amount of weight of any of the

patients (only 19 pounds) had very large hips and thighs and a

relatively small waistline and upper torso. Her WHR before surgery

was 0.68. Fat on the hips and thighs is broken down at a far slower

rate than fat in abdominal regions. Women who have large hips and

thighs and small waists generally have the greatest difficulty

losing weight following surgery or with any other anti-obesity

procedure. may, therefore, have lost the least amount of

weight post-surgery because most of her fat was stored on her hips

and thighs where fat turnover is slow.

Differences in fat distribution could not explain why , Sally

and Sue's weight losses differed, as all three had a similar WHR.

(Remember: had lost 57 pounds, Sally 40 pounds, and Sue only

29 pounds.) The three females also had similar starting weights.

Furthermore, exercise habits could not account for differences in

these patient's postoperative weight losses, as all three patients

were participants of the same postoperative exercise program.

Nutritional profiles, however, did provide a clue as to why Sue's

weight loss post-surgery differed from and Sally.

At our clinic, nutritional profiles are obtained from patients' food

diaries at each of their follow-up visits. Nutritional information

obtained from these profiles include total calorie intake, the

percentage of diet that is protein, carbohydrate and fat, the types

of protein, carbohydrate and fat consumed, and dietary vitamins and

minerals. We found that and Sally's nutritional profiles were

similar with regard to daily calorie intake and dietary composition.

Sue's diet, however, significantly differed.

Sue was eating an average of 250 calories more per day than

and Sally. In addition, Sue was consuming fewer calories as protein

and more calories high in sugar-containing carbohydrate. Sue's

greater intake of sugar-containing carbohydrate, coupled with the

slightly greater number of calories she was consuming each day,

could have contributed to the lower weight loss she experienced when

compared to the weight losses of and Sally.

Sugar-containing carbohydrate and processed grains increase insulin

to levels higher than would occur if fiber-rich carbohydrates were

consumed, such as fruits, whole grains, nuts, legumes, vegetables.

Insulin, in turn, drives fat into fat storage depots and reduces the

breakdown of fat, thereby adversely affecting weight loss success.

Sue's diet was not only higher in simple carbohydrates but was also

lower in protein than the diets of and Sally. Eating

sufficient amounts of protein helps prevent the breakdown of muscle

and other lean body tissue that may occur post-surgery or with low

calorie diets. Muscle has high metabolic activity and oxidizes

(burns) fat. A loss of muscle or other lean body tissue, therefore,

would reduce metabolic activity and fat metabolism.

Over the 3-month postoperative period, Sue lost proportionately more

muscle and other lean body tissue and proportionately less fat than

did or Sally. (Note: body composition was measured by

bioelectric impedance). Sue also had a greater reduction in basal

metabolic activity (measured by indirect calorimetry) in association

with her loss of muscle and lean body tissue. Basal (resting)

metabolic activity accounts for up to 70% of all calories burned

during the course of the day. Sue's failure to lose weight as

effectively as and Sally, therefore, could have resulted, in

part, from her postoperative loss of lean body tissue and decreased

basal metabolic rate.

Sue's poor nutritional profile, her greater muscle and lean body

tissue loss with surgery and reduced basal metabolic activity could

explain why she lost less weight than did or Sally. However,

differences in nutritional profiles, body composition, and basal

metabolic activity, as well as fat distribution, initial body size,

and levels of physical activity do not explain why Sally lost less

weight with surgery (17 pounds less) than did , since all of

these measures were similar.

Why, then, would Sally have lost less weight than ? According

to Sally's 3-month postoperative clinical records, she was still

taking diabetes medication (a sulfonylurea) to control her blood

sugar, albeit at a lesser dosage than before surgery. She was also

taking a beta-blocker for hypertension. , on the other hand,

was on no medication.

Ironically, many medications used to treat diseases caused or

worsened by obesity increase body weight. Most diabetes medications

(except metformin) cause fat accumulation and weight gain, including

insulin, sulfonylureas and the thiazolidinediones. Many anti-

depression medications or mood stabilizers also cause weight gain,

especially lithium and the tricyclic antidepressants. In addition,

steroids used to treat osteoarthritis or autoimmume disorders

increase body weight and fat accumulation, as do beta-blockers and

calcium channel blockers for hypertension.

It is likely that Sally's diabetes and hypertension medications were

responsible for her inability to lose as much weight as .

However, there could have been factors other than medication, diet,

exercise, metabolic rates, or fat turnover that caused post-

operative differences between Sally's or 's weight losses or

those of other patients in the group.

One patient may have lost less weight than another because their

growth hormone levels were low, sex hormone production was altered,

or cortisol levels were high. Defects in hormones, gut factors or

neurochemicals that regulate food intake, satiety and energy

expenditure may also have caused variability in patient post-

surgical weight loss. Altered activities of enzymes regulating fat

metabolism or energy utilization may have influenced rates of post-

surgical weight loss. Genetics could have contributed to weight

changes, as could numerous other conditions that influence energy

intake or expenditure.

Why, then, does one patient lose more weight than another with

surgery? For numerous reasons, including differences in calorie

intake, energy expenditure, body habitus and body composition, basal

metabolic activity, hormone profiles, genetics and much more.

Because weight loss is regulated by such a myriad of factors, it

would be highly unlikely that any two individuals would lose

identical amounts of weight post-surgery, even if they were

consuming the same amount of calories and performing similar amounts

of physical activity.

Therefore, it is important that healthcare professionals realize

that identical surgical procedures do not result in identical weight

loss patterns and that weight reduction is regulated by far more

than calories in and calories out. Furthermore, patients should not

despair or feel unsuccessful if they have lost less weight than

others, particularly if they have been honest in adhering to their

postoperative dietary and exercise regimens.

Buffington is the Director of Research, U.S. Bariatric, Fort

Lauderdale, Miami, Orlando

Originally Published in Beyond Change - 2004