Nutritional Guidlines

It is very important that you follow a strict diet after your gastric bypass

Following surgery, you will need to follow a specific nutritional plan for the first five weeks. This is very important. By following the nutritional guidelines set out below, you will reduce the chances of experiencing a bypass complication and give yourself a good start to your weight loss journey.

There are three phases to your post-op diet.

These three phases are set out in more detail below for you.

Nutritional Advice

Phase 1: Liquid foods

You must follow a liquid diet for the first two weeks after your bypass operation. This is to allow time for your body to heal and recover. If you move onto foods too quickly it can put pressure onto the staple lines which could cause them to rupture. This would mean stomach contents would leak into your abdomen which is very dangerous. Please note that post-operative advice does vary between surgeons – if you are unsure of what to do, please contact us. 

It is important to focus on high protein fluids to ensure your body can heal well. Have a look at our patient guide to give you ideas on what to drink in order to meet your protein goal.

  • Liquids should be smooth and not contain any ‘bits’ as they may cause discomfort or pain or get stuck. Use a sieve if you are unsure
  • If a drink will go through a straw then it is the correct consistency for this stage. However, do not drink through a straw as you may take in a lot of air and this could cause discomfort
  • Sip slowly but frequently throughout the day at the start of the liquid stage, allowing a few minutes between sips. As the days go by, you can progress to cupful’s of drinks taken slowly over a 15 – 20 minute period. In the first two weeks after surgery, you can build up to taking around 200mls at any one time. If you experience pain, discomfort or regurgitate your drinks, take smaller sips and allow more time between sips. Some people find warm drinks go down more easily to start with; others find that sucking ice cubes can help if you are struggling to get fluids down
  • Avoid fizzy drinks in the early days after your operation as these may cause pain from trapped wind. Make sure that your drinks (especially nutritional drinks) are spread out over the day. If you go for long gaps without anything to drink you may start to feel light-headed and nauseous
  • Some people get a ‘furry mouth’ in the first month as when you have nothing to chew on, your mouth produces less saliva to protect your teeth. Using a mouthwash and brushing your teeth well will help. You could also try sugar free chewing gum, ice cubes and home made no added sugar squash ice lollies.

Phase 2: Puréed foods

Two weeks after your bypass operation, the stomach tissues are still healing and it remains important not to stretch the small stomach with foods that are hard or indigestible. You should begin to make the transition from liquids to puréed foods at the start of week 3. At the start of week 4 start to transition to soft foods. Do not eat larger quantities than recommended even if you feel that you could.

Have a look at our patient guide that helps give you ideas of pureed and soft meals.

It’s best to avoid more ‘difficult’ foods at this stage such as red meat, shellfish, bread (especially really fresh), fibrous fruit and vegetables including skins, dried fruit, nuts and rice. Fish and white meat are generally softer than red meat and can be mashed, although well-cooked lean minced meat in sauce would be fine. If your food is ‘spoonable’ it is the correct consistency. 

  • Start by eating up to 6 small puréed ‘meals’ per day and then towards the end of this stage try to establish a 3 meal a day pattern of eating with soft foods
  • Your portion size should be about 3 – 6 tablespoons per meal. Never exceed 6 tablespoons for each meal even if you feel you could eat more. Serve your meals on a 7 inch side plate
  • Eat very slowly (take 15 – 20 minutes for each meal) to prevent any pain or discomfort. Your timer can help you to slow down your eating

Phase 3: Normal foods

This stage is really the start of learning how to work with your gastric bypass developing lifelong healthy eating habits to achieve your health and fitness goals. You must leave soft, sloppy food in the past and discover solid textured foods that remain longer in your stomach to stop you from feeling hungry.  

What should I eat? 
For your bypass to work effectively, food now needs to be of a ‘drier’ consistency, eaten and chewed slowly in small mouthfuls so that you learn to sense fullness and stop eating when you think you’ve had enough. From now, you can eat all foods but if you are introducing a food for the first time, we recommend you try it at home and chew it well so that you are confident you can eat it without discomfort or regurgitation. Be particularly careful with any of the ‘difficult’ foods that you may have avoided last month i.e. red meat, shellfish, bread (especially really fresh), fibrous fruit and vegetables including skins, dried fruit, nuts and rice. If you experience discomfort or food ‘sticking’ the first time you eat it, try again a week or two later perhaps chewed slightly longer and eaten even more slowly so that you know how much you can manage. 

  • Choose healthy, wholesome foods and no junk food. Your new eating plan has no room for wasted calories from sugary, fatty foods and your emerging new body needs good nutrients to keep you healthy and full of energy. Most fast foods and snacks are high in fat, salt or sugar. These are not good for your health or energy levels
  • Always choose foods low in fat and sugar. Yogurts and similar products like fromage frais should be ‘diet’ i.e. low in fat AND sugar. Meat and poultry should have fat and skin removed. Food should be baked, grilled, microwaved, steamed or stir fried, not deep fried. You then taste the food, not oil.

What shouldn’t I eat? 
Leave behind the milkshakes (protein shakes are okay), smoothies, gravy and sauces that you had in the last few months. Soft and liquid foods are not recommended because one tends to consume large volumes of them quickly, they pass through your system and you will soon be hungry again. If you frequently consume soft foods and drinks that are high in fat and sugar e.g. ice cream, cake, chocolate, milk shakes etc OR high calorie ‘crunchy’ foods such as crisps, biscuits etc you will not feel full and you will be tempted to consume larger quantities. This will prevent further weight loss and may lead to weight gain. 

How much should I eat? 
Your main meal should fit onto a 7-inch side plate or small bowl and be composed of foods in the following proportions:

  • One half protein (e.g., meat, poultry, fish, pulses)
  • One quarter carbohydrate (e.g., potato, pasta, rice, bread, couscous)
  • One quarter vegetables or salad (without butter, mayonnaise or rich dressings)

There’s much more help in our patient guides!

Call our specialist team today on
0800 313 4618 
or
Get a quote 
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