Dumping syndrome and reactive hypoglycaemia after bariatric surgery

Dumping syndrome

What is dumping syndrome?

Dumping syndrome can occur after eating foods high in fat and sugar and may cause a range of symptoms.

It often develops within a few hours of a meal. Symptoms can include:

• abdominal pain and cramping
• bloating
• diarrhoea
• increased heart rate
• flushing
• fatigue
• palpitations
• sweating
• hunger
• shakiness

These symptoms happen because food, particularly carbohydrate, moves rapidly into the small intestine. This can draw extra fluid into the intestine and carbohydrates may be absorbed quickly, causing a rise in blood glucose.

In response, the body releases insulin, which can sometimes lower blood glucose too much, leading to further symptoms such as tiredness and shakiness.

How do I know if I have dumping syndrome?

If you are experiencing symptoms that match those above, you may have dumping syndrome.

Some people have mild symptoms, while others experience more severe symptoms or a mixture of the two types.

The best way to track your symptoms is to keep a food and symptom diary, noting what you eat, when you eat it and when you develop any symptoms afterwards.

What can I do if I experience dumping syndrome?

If you start to experience symptoms of dumping syndrome after eating, there are some simple steps that may help relieve them:

• sit or lie down and try to rest until the symptoms pass
• avoid drinking fluids at the same time, as this can worsen symptoms
• loosen any tight clothing and focus on slow, steady breathing to help with discomfort

Symptoms usually settle on their own within a short time. However, if they are severe or happen frequently, speak to your healthcare team for further advice and support.

If you have diabetes, please speak to the healthcare team that manages your diabetes care.

What can I do to prevent symptoms of dumping syndrome?

Strategies that may help prevent symptoms include:

• wait at least 30 minutes between eating and drinking to prevent fluid pushing food into your intestine too quickly
• reduce your portions to within the recommended size or have smaller meals more frequently, spreading the same amount of food across more mealtimes
• reduce or avoid foods high in sugar and fat
• focus your meals around foods high in protein and fibre
• choose slowly digested carbohydrates, such as potatoes with the skins on, brown pasta, brown or basmati rice and wholemeal bread
• avoid alcohol
• eat slowly, taking around 20 minutes to eat a meal
• chew all your food thoroughly, around 20 times, and keep each mouthful approximately the size of a 20p piece

If these recommendations do not help, you can also try lying down for 30 minutes after your meal to slow down how quickly food is digested.

What happens next?

Understanding the causes of dumping syndrome can help prevent further symptoms, which is why a food and symptom diary is useful to your healthcare team. It can also help you identify patterns yourself.

If you keep a food and symptom diary, please bring it to your next appointment with the dietitian so you can discuss it together.

If the advice above does not relieve your symptoms, speak to your dietitian or surgeon. There are other approaches that may be considered depending on your symptoms, including medication, but these should be used under professional supervision.

Reactive hypoglycaemia

Reactive hypoglycaemia is the general term for hypoglycaemia, or low blood glucose levels, after eating.

It usually occurs a few hours after a meal, snack or drink, typically within 1–4 hours, and is a recognised complication after bariatric surgery.

What are the symptoms of reactive hypoglycaemia?

If these symptoms occur within 1–4 hours after eating, you may be experiencing reactive hypoglycaemia:

• feeling sweaty
• hunger
• anxiety
• shakiness
• confusion
• dizziness
• difficulty coordinating movement
• slurred speech
• loss of consciousness
• palpitations, or a rapid heart rate

Why does reactive hypoglycaemia occur?

Reactive hypoglycaemia is the result of anatomical changes to your gut and changes to gut hormones that occur after bariatric surgery and affect the way carbohydrates, or sugars, are digested and absorbed.

Reactive hypoglycaemia is closely linked to your diet and can often be managed with dietary changes.

How reactive hypoglycaemia develops

• A meal containing carbohydrates, or sugars, is eaten.
• Food enters the stomach and digestion begins.
• Food empties from the stomach into the small intestine and absorption begins.
• Carbohydrate absorption causes an increase in blood glucose levels and activates the release of gut hormones.
• Rising blood glucose levels and gut hormones stimulate insulin production, which can sometimes be excessive.
• Excessive insulin causes blood glucose levels to fall.
• Symptoms of reactive hypoglycaemia occur.

Gut hormones: GLP-1 and gastric inhibitory polypeptide.

Insulin is released in response to an increase in blood glucose levels. Its role is to control blood glucose levels by signalling to the liver, muscles and fat cells to use glucose from the bloodstream for energy. If the body's cells have enough energy, insulin signals to the liver to store glucose as glycogen.

How is reactive hypoglycaemia diagnosed?

Keeping a food and symptom diary can help confirm whether any foods you eat are triggering symptoms.

Record the type and amount of food eaten, the times of your meals and the times of any symptoms using the diary in this leaflet.

This information can be shared with the dietitian, who can advise on dietary changes to help improve your symptoms.

If the dietitian is unable to help you manage your symptoms, or your symptoms are severe, you will be referred to an endocrinologist for further investigation and management.

Which foods contain carbohydrate?

Carbohydrates can be divided into 2 groups: starchy, or complex, carbohydrates and free sugars.

Carbohydrates are found in foods including:

• pasta
• couscous
• breakfast cereals
• crackers
• rice
• fresh, tinned and dried fruit
• starchy vegetables such as potatoes, yam and sweet potato

All of these are digested by your body to release glucose, or sugar.

Processed foods that contain carbohydrates in the form of free sugars include:

• cakes and biscuits
• sweets
• chocolate
• fruit juice and smoothies
• jam and marmalade
• honey

Adapting your diet to manage reactive hypoglycaemia

1. Eat small portions of food more regularly across the day

Make sure meals and snacks are structured and spaced 3–4 hours apart so you do not have long gaps between eating.

Eating 3 small meals and 2–3 snacks across the day can help stabilise your blood glucose levels and avoid symptoms that may be caused by eating large portions of food or carbohydrate.

2. Try to limit your carbohydrates

Aim for 30g of carbohydrate at each main meal and 15g at each snack.

Some studies have shown that limiting the amount of carbohydrate at mealtimes can help avoid rapid rises in blood glucose levels after eating, excess insulin secretion and the rapid drops in blood glucose that can cause symptoms of reactive hypoglycaemia.

To begin with, it may be helpful to calculate the amount of carbohydrate you are currently having at mealtimes and decrease it if that amount causes symptoms. For example, if you are having 2 thin slices of bread containing around 20g of carbohydrate and this causes symptoms, reduce this to 1 slice containing around 10g of carbohydrate to see whether this prevents reactive hypoglycaemia.

Later in this leaflet you will find a list of common foods with their average carbohydrate content, as well as other information you can use to calculate the carbohydrate content of food. Use your food and symptom diary to record the effects of any dietary changes.

3. Choose low Glycaemic Index carbohydrates

Carbohydrates are absorbed at different rates. Low Glycaemic Index (GI) carbohydrates are digested and absorbed more slowly than high GI foods. Including a small amount of low GI carbohydrate with your meals may slow the rise in blood glucose levels after eating and keep your blood glucose levels more stable afterwards. This may help prevent or reduce symptoms of reactive hypoglycaemia.

4. Meet your protein recommendations

Aim for an average of 70–100g of protein a day.

Eat protein with all of your main meals and choose protein-rich foods for snacks. Protein is important to preserve muscle mass after surgery and helps you feel fuller for longer. Remember to prioritise protein and eat it first during your meals or snacks.

5. Eat more fibre

Fibre-rich foods move more slowly from your stomach into your small intestine. This can help delay the increase in blood glucose levels after eating, decrease insulin secretion and reduce the risk of reactive hypoglycaemia.

Try to eat more fibre-rich, low GI foods such as:

• oats
• beans and pulses
• granary bread
• brown pasta
• brown basmati rice
• vegetables

6. Avoid eating and drinking together

Follow the ‘Golden Rules’ and separate eating and drinking. Avoid drinking within 15 minutes before eating and wait 30 minutes after meals or snacks before drinking. Eating and drinking together can increase the rate at which food empties from your stomach into the small intestine, which can cause a rapid rise in blood glucose levels and rapid insulin secretion.

7. Avoid sugary drinks

Avoid sugary drinks such as fruit juice, fizzy drinks, smoothies and milkshakes. These drinks are a source of carbohydrate in liquid form and are easily absorbed by the body. Sugary drinks can cause a rapid increase in blood glucose levels and insulin, increasing the risk of reactive hypoglycaemia.

Suitable alternatives include:

• water
• sugar-free squash
• tea
• coffee with sweetener

8. Avoid alcohol

Alcohol can affect the way your liver produces and releases glucose, so drinking alcohol may increase the risk of reactive hypoglycaemia. There is also some evidence suggesting an increased risk of alcohol dependency after bariatric surgery.

9. Keep a food, symptom and activity diary

A diary can be a useful tool for reflection. Keeping a record of when you eat, your symptoms and your physical activity can help you identify triggers. In the longer term, understanding your triggers can help you modify your diet to manage your symptoms.

Treating severe symptoms of hypoglycaemia

If you experience severe symptoms of hypoglycaemia, such as confusion, difficulty coordinating movement or slurred speech, you will need to take some fast-acting carbohydrate in the form of glucose to rapidly increase your blood glucose levels.

The guidance suggests around 15g of glucose. Suitable options include:

• 3 Jelly Babies
• 5 Glucotabs
• 5 Dextro Energy tablets
• 4 Wine Gums
• 175ml Lucozade Energy Original
• 60ml Lift Juice glucose shot

After 15–20 minutes, your symptoms should begin to improve. You should then eat a small carbohydrate snack if your next meal is not due. Choose a low GI carbohydrate with some protein, as this may help stabilise your blood glucose levels. A suitable option would be 1 or 2 oatcakes with some low-fat cheese or a slice of cooked meat.

The purpose of treating hypoglycaemia is to rapidly increase your blood glucose level and reduce the risk of more severe symptoms such as loss of consciousness. However, it is possible that a rapid increase in blood glucose after treating hypoglycaemia may trigger another episode of reactive hypoglycaemia after bariatric surgery.

If you notice this happening consistently, you could try reducing the initial amount of fast-acting glucose taken. A dose of 8–12g of carbohydrate has been suggested.

As advised above, follow this with a low GI carbohydrate and protein snack to help stabilise your blood glucose levels.

Food, symptom and activity diary

Example

Time	Food and drink consumed	Venue	Time of symptoms	Activity
12pm	2 slices of brown bread (approximately 28g carbohydrate), ham, tomatoes and a glass of water	Kitchen table	2.30pm – felt shaky and sweaty	Walked for 15 minutes, 1.15–1.30pm

Your diary

Time	Food and drink consumed	Venue	Time of symptoms	Activity

Glycaemic Index food table

The Glycaemic Index is a method of ranking carbohydrate-containing foods according to how they affect blood glucose levels. Low GI foods are digested and absorbed more slowly by the body, resulting in a more gradual and smaller rise in blood glucose levels and therefore insulin levels.

Combining low GI and high GI foods

If choosing high GI carbohydrates, it is useful to pair them with a high-protein, low GI food to slow the absorption of carbohydrate and make reactive hypoglycaemia less likely. For example, pair a jacket potato with tuna or chicken.

A note on fibre

High-fibre foods can help manage reactive hypoglycaemia by slowing the absorption of carbohydrate, leading to a more gradual rise in blood glucose and reducing sudden drops. Including foods such as wholegrains, vegetables, pulses and fruit can help keep energy levels more stable and reduce symptoms such as tiredness and shakiness.

Food	Low GI	Medium GI	High GI
Cereals	Oat-based cereal such as porridge, Oatibix or oat flakes Unsweetened muesli Special K All-Bran	Shreddies Weetabix Instant porridge	Bran Flakes Cornflakes Cheerios Rice Pops
Bread	Granary Rye Sourdough Pumpernickel Multigrain or seeded	Pitta bread Crumpets	Brown, white and wholemeal bread
Crackers	Oatcakes Seeded Ryvita		Rice cakes Water crackers
Potatoes and starchy foods	Sweet potato Yam Pearl barley Noodles	New potatoes Boiled potatoes Couscous Millet	Jacket potato Chips Mashed potato
Pasta	Most types
Beans and pulses	All types, such as lentils, chickpeas and baked beans
Fruit	Most types	Banana Melon Raisins Pineapple	Watermelon Dates
Vegetables	Most types		Swede Parsnips

Reading food labels to work out the carbohydrate content in foods

Typical values (bread)	Per 100g	Per 40g slice
Energy	934kJ	374kJ
Calories	221kcal	88kcal
Fat	1.8g	0.7g
of which saturates	0.4g	0.2g
Carbohydrates	37.8g	15.1g
of which sugars	4.1g	1.6g
Fibre	6.8g	2.7g
Protein	10.0g	4.0g

When reading food labels, nutritional information is often given per 100g of food. When trying to work out the carbohydrate content, check whether the information tells you how much carbohydrate is in the portion of food you are likely to eat.

The example above shows the carbohydrate content in a slice of bread. All carbohydrates are broken down in your body into glucose, or sugar, so you should use the total carbohydrate amount rather than the figure for ‘of which sugars’.

Calculating carbohydrate when information is not given per serving

In this example, the bread contains 37.8g of carbohydrate per 100g and one slice weighs 40g.

37.8 ÷ 10 = 3.78

This gives the carbohydrate content for 10g of bread.

A 40g slice contains four 10g portions:

3.78 × 4 = 15.1g carbohydrate

Therefore, one 40g slice of bread contains approximately 15.1g of carbohydrate.

The carbohydrate content of common foods

Bread products

Food and portion	Carbohydrate
1 thin slice of granary, white or wholemeal bread or toast	10g
1 medium slice of granary, white or wholemeal bread or toast	14g
½ bagel	25g
1 crumpet	17g
½ English muffin	15g
1 mini pitta	19g
½ wholemeal tortilla	15g
1 finger roll	21g
30g baguette	17g

Crackers and biscuits

Food and portion	Carbohydrate
1 oatcake	6g
1 water biscuit	5g
1 rice cake	6g
1 Ryvita Chia Seed & Buckwheat Protein	5.7g
1 oat biscuit	14g
1 Ryvita Multigrain Rye	5.8g
1 Ryvita Rye	6.7g
1 cream cracker	5.4g
1 high-fibre cream cracker	4.5g
1 Rich Tea biscuit	5g
1 digestive biscuit	10g
1 jam ring	13g

Cereals

Food and portion	Carbohydrate
27g raw oats with semi-skimmed milk	27g
30g Bran Flakes	22g
30g Cornflakes	27g
1 wheat biscuit	14g
30g Special K with berries	23g
35g granola	22g

Pasta and noodles

Weights shown are cooked weights.

Food and portion	Carbohydrate
50g macaroni	17g
50g penne	15g
50g spaghetti, white or wholewheat	17g
50g egg noodles	14g
50g rice noodles	18g

Rice and grains

Weights shown are cooked weights.

Food and portion	Carbohydrate
50g basmati rice	16g
50g brown rice	16g
50g long-grain white rice	16g
50g jollof rice	9g
50g pilau rice	12g
50g rice and peas	15g
50g quinoa	9g
50g couscous	13g
50g bulgur wheat	8g

Starchy vegetables

Food and portion	Carbohydrate
95g jacket potato	20g
65g boiled new potatoes	10g
55g baked sweet potato	15g
45g baked cassava	23g
60g boiled yam	20g
65g fufu	25g
33g oven chips	10g

Fruit

Food and portion	Carbohydrate
1 small banana	13g
1 clementine	5g
1 orange	8g
1 apple	9g
80g blueberries	7g
80g strawberries	5g
1 kiwi	5g

Vegetables

Food and portion	Carbohydrate
80g broccoli	2g
80g carrots	5g
80g cauliflower	3g
80g green beans	3g
80g peas	8g
80g peppers	2g
80g sweetcorn	11g
6 cherry tomatoes	4g

Pulses

Food and portion	Carbohydrate
80g kidney beans	13g
80g tinned lentils	14g

Yoghurt

Food and portion	Carbohydrate
125g low-fat Greek yoghurt	8g
125g fat-free fruit yoghurt	11g
125g low-fat natural yoghurt	10g
125g soya yoghurt	16g

Milk and milk alternatives

Food and portion	Carbohydrate
150ml skimmed, semi-skimmed or whole milk	7g
150ml unsweetened soya milk	1g
150ml semi-skimmed lactose-free milk	4g
150ml rice milk	15g
150ml almond milk	5g
150ml oat milk	11g
150ml coconut milk	7g

Drinks

Drink and portion	Carbohydrate
235ml cappuccino with skimmed or whole milk	8g
235ml latte with skimmed or whole milk	9g
235ml hot chocolate with skimmed or whole milk	25g
150ml apple juice	16g
150ml orange juice	12g
150ml smoothie	18g
150ml squash	3g

This list should be used only as a guide. Please refer to the nutritional information on food labels for accurate information.

Contact the Bariatric Dietitians

If you have any questions, please contact the Bariatric Dietitians.

T: 020 3315 8161
R: chelwest.bariatric.dietitians@nhs.net