Dietary Recommendations After Gastric Bypass Surgery
by: Protica Nutritional Research
When obesity gets out of hand, unresponsive to dietary, lifestyle
and medical interventions, drastic measures are needed to cut
down calorie intake. Morbid obesity with a BMI (body mass index,
a measure of malnutrition) above 40 kg/m2 is an indication for
surgical procedures such as gastric bypass surgery. Gastric
bypass is now a well-trodden path to lower BMI’s and
achieve healthier lives in 18 months or so. First used in the
1950’s, only the last two decades have seen safe and successful
gastric bypass surgery with any consistency. Half a century of
meticulous observations and patient follow-up has led to the formulation
of strict guidelines to ensure desired results.
Gastric bypass is a series of steps initiated
starting with the decision to undergo the procedure. Identifying
existing nutritional deficiencies is the first step towards surgery.
Vitamin and mineral deficiency often occur in obesity, and need
to be addressed before the procedure. The surgery itself has two
goals; to reduce the volume of the stomach and shorten the food
transit time in the intestine. After surgery the stomach cannot
receive large meals or participate in digestion. This by itself
limits food intake. Food also bypasses a large part of the intestine
and has little time to interact with liver and pancreatic enzymes.
As a result, nutrition absorbed from diet drops drastically. In
most types of gastric bypass surgeries
done today only 50 cm of the intestine is allowed to function
in normal fashion. Compare this to food absorption taking over
7 feet of small and large intestine before surgery.
With such a radical reduction in the capacity to assimilate food,
the postoperative period can be rather tricky. Only clear fluids
are advised for the first two days while waiting for gut to recover.
The gut is then re-trained for about two months before it can
go back to a normal diet. During the recovery period the limitations
imposed by the gastric bypass procedure should be kept in mind.
After surgery the stomach has become much smaller and can only
hold approximately eight ounces at a time. The stomach has also
lost its ability to pulverize food to initiate digestion. Consequently
the appropriate diet for postoperative recovery would be a liquid
to soft solid diet that can be taken six to eight times a day
in small quantities. Nutrient fluids are preferable since they
can provide hydration and energy at the same time. Non-nutrient
fluids are best avoided or at least restricted to in-between meals.
The type of nutrient chosen also deserves due consideration.
The chosen macronutrient should not affect the stomach emptying
time while providing enough energy to recover from the surgery.
In this regard carbohydrates and fats are at either end of a spectrum
and neither is suitable. Carbohydrates pass through very quickly
and produce very uncomfortable symptoms like vomiting, bloating,
diarrhea and sweating. Fat slows the gut considerably, and it
is oftentimes ruled out because of its direct link to obesity.
Research suggests that the macronutrients of choice after gastric
bypass surgery are proteins. Proteins do not change gastric transit
time significantly. A high-protein diet can also provide enough
amino acids for repair and growth after a major surgical procedure
like gastric bypass.
Apart from these advantages, a high-protein diet has a special
role in the treatment of obesity. Gastric bypass restricts excessive
calorie intake to prevent weight gain. However, accumulated adipose
tissue also needs to be expended to achieve the desired weight
loss. The basal metabolic rate (energy expenditure) should be
increased simultaneously to burn stored fat and reduce BMI. This
can be achieved by a high-protein diet since proteins in diet
increase the basal metabolic rate by stimulating protein synthesis.
Observations made during the postoperative period also confirm
this proposition. Unless a high-protein diet is provided, weight
loss often ceases despite controlled consumption.
Currently, a protein intake of up to 90 grams per day is recommended
in the post-operative period. Given the trauma and the limitations
the gut is subjected to during the procedure, such a high protein
intake can be difficult to maintain. The gut is hardly ready and
often fails to assimilate proteins and energy from traditional
foods and diets. Therefore, a sugar-free fluid protein concentrate
with a high bioavailability, adequate essential amino acids, vitamins
and minerals is the most appropriate diet in the post-operative
period. Digestion is further facilitated if the protein concentrate
is already pre-digested, or hydrolyzed. Such a nutrient fluid
can simultaneously supply concentrated energy and hydration even
when taken in small quantities.
After recovery and return to a normal diet divided over 3 to
4 meals per day, a high-protein concentrate is still a relevant
supplement between or during meals. The protein supplement continues
to provide thermogenic action necessary to lose weight essential
to sustain weight loss. It also compensates for any amino acid
deficiency in the diet and maintains nutrition on bad days not
uncommon in the months and years after a major surgery.
REFERENCES
1. Kellum JM, DeMaria EJ, Sugarman HJ. The surgical treatment
of morbid obesity. Curr Prob Surg. 1998;35:791-858.
2. MacLean LD, Rhode BM, Nohr CW. Late outcome of isolated gastric
bypass. Ann of Surg. 2000. 231:524-528.
3. Nutritional Implications of Bariatric Surgery: Perspectives
of Practitioners Audiotape/Handout packages available post-conference.
4. Weight management—Position of ADA. J Am Diet Assoc.
2002;102:1145-1155
5. Faintuch J, Matsuda M, Cruz ME, et al. Severe protein-calorie
malnutrition after bariatric procedures. Obes Surg 2004; 14:175–181.
6. Alvarez-Leite J.I. Nutrient deficiencies secondary to bariatric
surgery. Curr Opin Clin Nutr Metab Care 7:569–575.
About The Author
Founded in 2001, Protica, Inc. is a nutritional research firm
with offices in Lafayette Hill and Conshohocken, Pennsylvania.
Protica manufactures capsulized foods, including Profect, a compact,
hypoallergenic, ready-to-drink protein beverage containing zero
carbohydrates and zero fat. Information on Protica is available
at http://www.protica.com
You can also learn about Profect at http://www.profect.com
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