Why preparation matters for your REMS scan
You may have seen other websites suggest that no preparation is needed for a REMS scan. That's partly true — the hip scan is rarely affected. But the lumbar spine scan is a different matter. It's performed through the abdomen, and bowel gas sitting directly in front of the vertebrae can obscure the very bones the scanner needs to see.
When the view is unclear, a few things can happen: the procedure takes longer and involves repeated breath-holds; the REMS practitioner may ask you to push out your tummy to help shift the gas; and very occasionally, if the scanner cannot gather enough valid data, the appointment needs to be rescheduled. A little preparation in the days before makes the whole appointment smoother — and this is especially true if you eat a high-fibre, vegetarian, or vegan diet.
The aim is simple: less gas in your bowel on the day of your scan. Most of that comes down to what — and how — you eat in the two to three days beforehand.
How ultrasound sees your bones
A REMS scan uses no radiation whatsoever. Instead, a handheld probe is placed on your skin with a small amount of gel and sends high-pitched sound waves — far beyond the range of human hearing — down into your body.
Those sound waves travel easily through fluids and soft tissue. When a wave reaches the boundary between two different tissue types, part of it bounces back as an echo. The probe detects these returning echoes and measures how long each one takes to return. From thousands of these echoes, the scanner builds a detailed picture of your bone mineral density and quality. In short: sound goes in, echoes come back, and your bone health is measured.
Why bowel gas blocks the ultrasound signal
Sound waves travel well through liquids and soft tissue because those materials are relatively dense and uniform. Gas is completely different. Air is thousands of times less dense than tissue, so when a sound wave hits a pocket of gas, almost none of it can pass through.
Instead, the wave is reflected and scattered in a disorganised way — like light hitting a shattered mirror. Two problems result: the scattered echoes create bright, confusing clutter on the screen, and almost no sound makes it past the gas to reach the spine behind it. That deeper region falls into an acoustic shadow — a blank, unreadable zone. The gas acts as a wall the sound simply cannot penetrate.
A clear signal path
Sound passes cleanly through tissue, echoes return, the bone is clearly measured.
Blocked by bowel gas
Sound scatters off the gas; an acoustic shadow hides the vertebra behind it.
This is why bowel gas is the most common cause of a difficult or incomplete spinal REMS scan. The spine sits deep in the abdomen with loops of intestine directly in front of it. Clear the gas, and you clear the path to an accurate result.
How the right food choices reduce bowel gas
Most bowel gas is not air you swallow — it's produced by the bacteria living in your gut as they break down certain foods, particularly those that are high in fibre or difficult to digest. Beans, cabbage, and fizzy drinks are well-known offenders for good reason.
The strategy is straightforward: for a couple of days before your scan, lean towards easy-to-digest foods that produce little gas, and ease off those that produce a lot. There's no need to starve yourself or follow a strict regime — just steer your plate in a gentler direction. The sections below tell you exactly what that looks like in practice.
Foods to choose and foods to avoid before your scan
Follow this guide for the 2–3 days before your appointment. You don't need to be perfect — just tip the balance towards the left-hand column as much as you can.
- Lean proteins — skinless chicken, turkey, white fish, eggs
- Plain, refined grains — white rice, white bread, plain pasta, crackers
- Well-cooked, peeled vegetables — courgettes, carrots, potatoes (no skin)
- Gentle fruits — ripe banana, melon, peeled soft fruit (in moderation)
- Clear soups & broths
- Still water & peppermint or ginger tea — sip steadily through the day
- Beans, lentils & chickpeas — the most significant gas producers
- Cruciferous vegetables — broccoli, cauliflower, cabbage, Brussels sprouts
- Onions, garlic & high-fibre foods — bran, raw leafy greens
- Fizzy drinks & beer — carbonation is gas you drink directly
- Fried & very fatty foods — slow digestion increases fermentation time
- Sugar-free gum & sweets — sorbitol and similar sweeteners cause bloating
If certain foods — such as dairy — normally leave you feeling bloated or uncomfortable, it's sensible to avoid those too in the days before your scan. Everyone's gut responds a little differently. The goal is a calmer digestive system, not a perfect diet.
Your day-by-day preparation plan
Here is how the guidance comes together in the days leading up to your appointment. Think of it as gently winding down gas production over a few days, then keeping things very simple towards the end.
Begin reducing gas-producing foods
Start trimming back beans, cruciferous vegetables, fizzy drinks, and very high-fibre foods. Continue eating normally otherwise — you're simply nudging your diet in a gentler direction.
Settle into easy-to-digest meals
Build your meals around the good choices list: lean protein, white rice or bread, and well-cooked, peeled vegetables. Keep sipping still water through the day to help things move along comfortably.
Keep meals light and unhurried
Stick firmly to gentle, easy-to-digest foods and eat smaller meals at a relaxed pace. Skip fizzy drinks entirely. Avoid chewing gum throughout the day so you swallow as little extra air as possible.
A short fast before your appointment
A few hours without food before your scan gives the best conditions for the spinal imaging. For a morning appointment, skip breakfast and drink still water only — you can eat a proper lunch afterwards. For an afternoon appointment, have a light breakfast, drink still water through the day, and skip lunch. An early supper after the scan will more than make up for it.
Helpful habits alongside your food choices
Beyond what you eat, a few everyday habits make a meaningful difference to the amount of air that ends up trapped in your digestive system:
Eat slowly and chew thoroughly. Eating quickly means swallowing significant amounts of air with every bite. Taking your time — and not talking too much mid-mouthful — reduces this considerably.
It also helps to avoid chewing gum and hard-boiled sweets in the days beforehand (both allow air to enter the gut steadily), to take a gentle walk after meals to help gas move through the system, and to avoid all carbonated drinks including sparkling water. None of this requires significant effort — it's simply a matter of small adjustments that stack together in your favour.
Quick-reference checklist
If you remember nothing else from this guide, keep this in mind: ultrasound cannot travel through gas. Clearing your bowel of gas is the single most effective thing you can do to help your REMS scan succeed at the first attempt.
Before your REMS scan appointment
- Start easing off gas-producing foods 3 days before your appointment.
- Choose lean proteins, refined grains, and well-cooked, peeled vegetables.
- Avoid beans, cruciferous vegetables, fizzy drinks, gum, and fried foods.
- Eat slowly, stay well hydrated with still water, and walk gently after meals.
- On the day, fast for a few hours before your appointment and drink still water only.
Common questions about preparing for a REMS scan
These are the questions patients most often ask — either before their appointment or after reading conflicting advice elsewhere. Each answer reflects the approach taken by Osteoscan UK.
A short fast is helpful, particularly for the spinal part of the scan. If your appointment is in the morning, skip breakfast and drink still water only — you can eat a proper lunch afterwards. For an afternoon appointment, have a light breakfast, then still water only until after your scan. This reduces the amount of bowel gas in front of the lumbar spine, where the ultrasound needs a clear path to the vertebrae.
Yes — it's the most common practical challenge in REMS spinal scanning. Ultrasound cannot pass through gas, so a pocket of bowel gas in front of the lumbar vertebrae creates an acoustic shadow that makes the bone invisible to the scanner. The scan may then take longer, require more breath-holds, or in some cases may need to be rescheduled. The three-day preparation approach on this page significantly reduces the risk of this happening.
Start reducing gas-producing foods around three days before your appointment. By the day before, aim to be eating mainly gentle, easy-to-digest food — white rice, plain pasta, lean proteins, and well-cooked peeled vegetables. A gradual wind-down over a few days is more effective than a sudden change the day before, as gas can take time to clear the bowel.
The most significant contributors are beans, lentils, and chickpeas; cruciferous vegetables such as broccoli, cauliflower, cabbage, and Brussels sprouts; onions and garlic; high-fibre foods like bran and raw leafy greens; all carbonated drinks including fizzy water; and sugar-free products containing sorbitol or similar sweeteners. These are all broken down by gut bacteria in ways that generate substantial gas.
Yes. If bowel gas prevents the practitioner from capturing a valid result for the lumbar spine, you may be asked to return on a different day. This is relatively uncommon when patients follow the preparation guidance, but it does occasionally happen — which is exactly why the two-to-three day dietary preparation is worth the effort. Following this guide gives you the best chance of a complete, accurate result at your first appointment.
That advice is partially correct but incomplete. The hip part of a REMS scan is rarely affected by bowel gas and requires very little specific preparation. The lumbar spine scan, however, is performed through the abdomen, and bowel gas directly in front of the vertebrae can significantly obstruct the ultrasound signal. If you eat a high-fibre diet, or a plant-based diet rich in pulses and cruciferous vegetables, preparation is particularly important for your spinal result.
Yes — still water is actively encouraged throughout the preparation period and on the day itself. Staying well hydrated helps keep your digestive system moving and does not contribute to bowel gas. The important thing is to avoid sparkling or carbonated water, as the bubbles introduce gas directly into the gut.
Yes — preparation is especially important if you follow a plant-based diet. Vegetarian and vegan diets tend to be rich in exactly the foods that produce the most bowel gas: pulses, beans, cruciferous vegetables, and high-fibre wholegrains. Temporarily swapping these for white rice, plain pasta, well-cooked peeled vegetables, and eggs or firm tofu for the two to three days beforehand makes a meaningful difference to the quality of your spinal scan.
