Dietetics - Polymeric Diet

When you eat and drink, food travels firstly to your stomach and then enters the rest of your gut where it is broken down and absorbed.

In certain diseases (e.g. Crohn's Disease) your gut can become inflamed. This can happen anywhere along the tract but is more common in the lower part of the small bowel and in the large bowel. This inflammation can prevent the absorption of nutrients from the food you eat.

Good nutrition is one of the ways the body restores itself to health. Not absorbing enough nutrients from your food over a long period of time can lead to malnutrition. Common signs of malnutrition include weight loss, poor wound healing, and tiredness as well as many others.

As part of your treatment, you may be asked to trial a 'therapeutic liquid only diet' (may also be referred to as a Polymeric Diet) for a short period of time. A liquid diet is helpful as it can avoid the use of certain medications by allowing the bowel to rest and helping it to heal. It can also help you to feel better and stronger.

A liquid diet is usually followed for a minimum of 2 weeks up to a maximum of 8 weeks. The diet involves drinking only special nutritional supplements, which you will receive from your GP, for the duration of the diet. These supplements will provide all the nutrition your body needs - your dietitian will recommend how many you will need to take.

The supplements come in a range of different flavours to help you stick to the diet which is useful as you may be asked to drink a large number of these drinks per day. This is to ensure your body is provided with the right amount of energy, protein, vitamins and minerals. You will be offered a selection of these to sample to identify the ones you tolerate best.

In addition to these supplements, you can drink water or herbal decaffeinated teas e.g. peppermint. It is important you do not eat or drink anything else unless agreed otherwise with your dietitian.

After you have completed the diet, your dietitian will give you advice on reintroducing food back into your diet. If you feel you are struggling to stick to the diet, then contact your dietitian and further advice can be given.

Food reintroduction

After the period of liquid-only diet has been completed you can begin to slowly reintroduce food into your diet.

The information below is to be used as stop-gap advice. Your dietitian will be able to provide you with more information and a diet sheet about suitable food choices for re-introduction when appropriate.

It is likely that a half and half approach using nutritional supplements and low-fibre food choices will be used before eventually progressing to full diet.

Each nutritional supplement usually provides approximately 300kcals and 14g protein.

The following meals/snacks are roughly equivalent to a nutritional supplement for energy and protein.

When reintroducing food aim to swap 1 or 2 nutritional supplements with one of the meal choices below:

• Jacket potato with tuna (avoid the potato skin and have only the middle of the potato)
• Jacket potato with cheese (avoid the potato skin and have only the middle of the potato)
• 2 slices of toast (white bread) with butter and Jam (seedless/ smooth jam only) or Marmite
• Sandwich (x2 slices white bread) with ham/beef/chicken/tuna/ cheese filling
• Small portion (~60g) of white pasta/rice or potatoes (no skins) with chicken/white fish/cheese