Why is it hard to gain weight?

After surgery, absorption may fall, diarrhoea may increase, or eating drops for fear of pain. Your doctor first looks for active disease, a narrowing, or treatable causes of diarrhoea.

Steps to gain weight

• Six small meals instead of three large ones, with a snack about every 2–3 hours.
• Protein at every meal: eggs, chicken, fish, laban, full-fat yoghurt, cheese; about 1.2–1.5 g per kg of body weight daily Proven
• Add energy without adding volume: a spoon of olive oil over rice or vegetables, peanut butter or tahini, milk fortified with milk powder, avocado.
• Liquid nutritional supplements (medical formula), one or two bottles a day between meals, of the type your dietitian chooses Proven
• Nourishing snacks: bread with cheese or egg, laban with dates, muhallabia or rice pudding, banana milkshake.
• Do not avoid whole food groups out of fear without a clear reason; restriction makes weight loss worse.
• Weigh yourself weekly; a practical target is about 0.5–1 kg a month.

If part of your small bowel was removed

• Regular vitamin B12 injections if more than 20 cm of the last part of the small bowel was removed Proven
• Vitamin D, zinc, magnesium, iron and folate are checked regularly and replaced according to results Proven
• If diarrhoea is watery after surgery, it may be caused by bile acids, and your doctor can prescribe effective medicines Proven
• With a long ileal resection and the colon still in place: reduce large amounts of visible fat, and reduce oxalate-rich foods (spinach, strong tea, large amounts of nuts, chocolate) to lower the risk of kidney stones, and drink enough water Proven

If you have an ileostomy or high output

• Foods that thicken output: rice, potato, pasta, white bread, banana, oats, peanut butter.
• If output is more than 1.5 litres a day: drink oral rehydration solution, limit plain water, tea and juice to about 1 litre a day, and add salt to food Proven This is the opposite of the usual advice to drink lots of water.
• Drink half an hour before or after meals rather than with them May help
• To avoid stoma blockage: chew well and limit coarse fibre (whole corn, popcorn, whole nuts, fruit skins, mushrooms, large amounts of dried fruit, orange pith).