Should I Eat Before A Drug Test


Should i eat before a drug test? it’s important to understand why drug tests are given in the first place. The reason why there are so many drug tests given is because they help employers reduce the risk of hiring a new employee that is a drug user. These types of employees are very high risk as they tend to show up late, if at all and generally don’t perform well on many levels. Also, if you make mistakes on the job involving equipment, chemicals, or money there may be severe consequences – even death in the case of working with heavy machinery or power tools.

Drug Testing

What is a Drug Test?

A drug test looks for signs of one or more illegal or prescription drugs in a sample of your urine (pee), blood, saliva (spit), hair, or sweat. The purpose of a drug test is to look for drug use and misuse, which includes:

  • Using any illegal drugs, such as cocaine or club drugs
  • Misusing prescription medicines, which means taking prescription medicines in a different way or for a different purpose than your provider prescribed. Examples of drug misuse include using a prescription pain reliever to relax or taking someone else’s prescription.

A drug test can check for a single drug or for a group of drugs in your body. Drug tests commonly test for:

  • Alcohol
  • Amphetamines, including methamphetamine
  • Barbiturates, such as phenobarbital and secobarbital
  • Benzodiazepines, such as alprazolam or clonazepam
  • Cocaine
  • Marijuana (THC)
  • Opioids and opiates, such as heroin, codeine, oxycodone, morphine, hydrocodone, and fentanyl
  • Phencyclidine (PCP)
  • Steroids

Most drug tests use urine samples. These tests can find signs of drugs within hours to several days or more before the test. How long a drug lasts in your body depends on:

  • The type of drug
  • How much you used
  • How long you were using it before the test
  • How your body reacts to the drug

Other names: drug screen, drug test, drugs of abuse testing, substance abuse testing, toxicology screen, tox screen, sports doping tests

What is it used for?

Drug testing is used to find out whether you have been using or misusing one or more drugs. But it can’t diagnose a drug use disorder (addiction).

A drug test may be used for different purposes, including:

  • Employment. Employers may screen you for drugs before hiring you. After you’re hired, they may test you to check for on-the-job drug use. If you have a work accident, you may be tested to see whether drugs or alcohol were involved.
  • Sports. Professional and other athletes are often tested for drugs that are used to improve performance, such as steroids that help build muscle.
  • Drug treatment. Drug testing may be used to monitor treatment in programs for drug or alcohol use disorder.
  • Legal evidence. Testing may be part of a criminal or motor vehicle accident investigation. Drug screening may also be ordered as part of a court case.
  • Monitoring misuse of prescription drugs. If your provider prescribed a medicine that can be addictive, such as an opioid for long-term pain, your provider may order a drug test to make sure you’re taking the medicine correctly.

Dietary Restrictions for Urine Tests

Observing Dietary Restrictions Avoids False Urine Test Results

Certain foods and drugs ingested before or during the collection of a urine specimen can interfere with the accurate results of some tests. In general, you should observe the dietary restrictions listed here if you have one of these tests. If, however, your test is not listed here, there are no dietary restrictions you need to observe. Consult your doctor before discontinuing any medications, or if you are unsure whether a drug you are taking is listed here. In any case, always follow your doctor’s specific instructions for the test ordered.

Metanephrine Urine Test

If your doctor has ordered a test for metanephrine in your urine, you should avoid caffeine for 24 hours and during collection of your specimen. In addition, the following drugs should be avoided for one week prior to the collection, if clinically feasible:

  • Phenothiazines (used to treat mental or emotional disorders)
  • Tricyclic antidepressants including imipramine, as well as labetalol, sotalol and monoamine oxidate inhibitors (MAOIs)
  • Chlorpromazine (used to treat psychosis)

Caution: do not stop taking any medications without prior approval from your physician.

Vanillylmandelic Acid (VMA) Urine Test

If your doctor has ordered a test for VMA in your urine, you should avoid high doses (as determined by your physician) of the following substances for a minimum of 24 hours before, as well as during, collection of your specimen:

  • Triamterene (used to treat high blood pressure and fluid retention)
  • Octopamine (found in drugs such as Norfen, Norden and Epirenor)
  • Phenolic amines (found in fruit juices and bananas)
  • Phenylpyruvic acid

You also should avoid the drugs labetalol and methyldopa, both of which are used to treat high blood pressure.

Caution: do not stop taking any medications without prior approval from your physician.

Hydroxyindoleacetic Acid (5HIAA) Urine Test

If your doctor has ordered a test for 5HIAA in your urine, you should avoid the following foods and drugs for at least a 48-hour period before and during collection of your specimen:

  • Bananas
  • Avocadoes
  • Plums
  • Cantaloupe and honeydew melon
  • Dates
  • Hickory nuts
  • Grapefruit
  • Kiwi
  • Eggplant
  • Tomatoes
  • Pineapples
  • Walnuts
  • Plantain
  • Pain relievers (specifically those containing acetaminophen, salicylates or phenacetin)
  • Cough syrups containing glyceryl guaiacolate
  • Muscle relaxants containing mephenesin or methocarbamol
  • Antidepressants including imipramine and monamine oxidase inhibitors (MAOIs)
  • Isoniazid (antibiotic used to fight tuberculosis and other diseases)
  • Methenamine (antibiotic used to fight urinary tract infections)
  • Methyldopa (used to treat high blood pressure)
  • Phenothiazines (used to treat mental or emotional disorders)

These foods can make you test positive for drugs

There’s nothing worse than when your dog actually did eat your homework, but you’re still not believed.

Unless of course you’ve tested positive for opiates and your alibi is that you ate some bread rolls.

This is the claim of a 58-year-old pipe fitter, suspended from work for 11 weeks after testing positive for morphine – an extract from the opium produced by poppies.

Speaking to the Liverpool Echo, the father of two, who wishes to remain anonymous, insists the test reading was the result of him eating poppy seed bread and buns the day before the test.

After receiving the positive results, the Liverpudlian paid £120 for a private hair-follicle test, which came back negative, and obtained a letter from his GP stating he had never been on any prescribed medication, such as morphine or painkillers – which contain opium.

“I am a married dad and have two grown-up children. I have never taken drugs,” said the Liverpool man.

“I thought to myself ‘I have something in my body that I have no idea where it has come from’ – it was very worrying.”

Negative test resultsHandout

The pipe fitter’s online research led him to an experiment on BBC One’s Rip Off Britain: Food, which aired in May. Over three days, 72-year-old presenter Angela Ripon ate a loaf of poppy seed bread and a poppy seed bagel to see if a drug test would pick up opiates. The results showed the presence of morphine.

The construction worker added, “I knew straight away that it had to be the poppy seeds I had eaten and I actually thought ‘Great that explains it.’”

His company have since taken him back, although the contractor that he failed the test for has refused to accept his return to work.

So, can eating poppy seeds really lead you to fail a drug test?

Yes indeed.

“If you eat a poppy seed roll, it could give rise to a positive result on a urine drug test for morphine,” says Atholl Johnston, Professor of Pharmacology at Queen Mary University.

While the morphine content of poppy seeds can vary by a factor of nearly 600, drug tests are highly sensitive, and could return a positive result even after a relatively small number of the seeds.

However, Professor Johnston makes it clear that eating poppy seeds will not get you high any time soon.

“It is unlikely that a single poppy seed roll, or even a dozen rolls, would result in an individual ingesting enough morphine to have a pharmacological effect.”

Nevertheless, it’s advisable to wait up to three days after eating poppy seed products before taking a drug test.

And in case you’re wondering what other kinds of foods could lead you to fail a substance test, we’ve got the answer for you: the best kinds.

Like pizza and pastries.


Now a fair number of people would probably testify that pizza is effectively an addictive drug anyway.

But according to a breathalyser manufacturer, food products that use yeast can in fact make you fail a breathalyser test. This is because yeast makes dough rise by fermenting sugars into a number of substances, one of which is alcohol.

And if you’re unlucky enough to be breathalysed immediately after eating pizza, then this could cause you to fail the test.

According to the same source, this also applies to ripe fruit and fruit drinks. These can ferment and produce just enough alcohol for you to test positive.

Thankfully, because the alcohol is in your mouth rather than in your digestive system, you should be fine after about 15 minutes. Alternatively, you can rinse your mouth out with water.

Then there’s hemp seeds (often found in granola bars), hemp seed oil and hemp seed milk.

hemp seedsiStock

These can lead you to test positive for THC, the principal psychoactive chemical in weed. After all, hemp is itself a type of cannabis.

And even poor, innocent, tonic water can help you to fail a drug test.

tonic wateriStock

Tonic water was originally drunk for its quinine, an antimalarial drug derived from the bark of the South American cinchona tree.

This led to the invention of gin and tonics by a British official in 19th-century colonial India, who found a way to liven up the anti-malarial prescription.

But having a few G&Ts could also liven up your drug test results.

Quinine is sometimes used to cut illegal drugs like heroin, and the amount of quinine present in your drinks can return urine test results that mirror those of drug users.


1. Interpretation

A qualified and trained toxicologist (a chemist, biochemist, medic, pharmacist, forensic scientist or similar) should interpret every single test to rule out any extenuating circumstances that could affect the results. Without trained interpretation, it is impossible to draw a valid conclusion. Interpretation, though, should be shared with the requester of the test. A lawyer may not have the expertise or knowledge to judge whether the subject’s behaviour is consistent with the results, thus needing a clinical opinion from a counsellor or other medical advisor. This will, of course, depend on why the test has been requested in the first place.

2. Sample collection and chain of custody

Every test should be subject to stringent processes for sample collection, which will avoid the risk of mistakes or tampering. The chain of custody – which involves the documentation and traceability of the entire testing process – everything that was done, who it was done by, and a timestamp for every part of the process. This ensures that we can reconstruct the entire analysis for court proceedings, with 100% confidence and accuracy.

3. Time between collection and test

The longer the time that passes between collection and test, for certain tests, the more likelihood there is of external factors (like temperature) affecting the sample. This tends to affect liquid samples more than hair samples: the stability of the latter can be advantageous where time is an issue.

Urine testing

4. Hydration/dilution

In some instances, excessive water consumption can lead to a donor’s urine sample becoming diluted, thereby reducing the quantity of a drug that can be detected and causing the concentration detected to fall below the relevant cut-offs. This will generate a false negative – although the laboratory should be capable of checking the concentration of the urine through testing the specific gravity or the urine’s creatinine concentration.

5. Tampering

Because of the level of privacy required for a donor to produce a sample, it is possible for them to switch samples, or dilute them with water. Donors could even adulterate urine samples with nitrites to minimise the chances of drugs being detected.

Because of the level of privacy required for a donor to produce a urine sample, it is possible for them to switch samples

6. Metabolic profile

Humans are all built differently, and that includes our metabolism. Active metabolism won’t hide drugs in the system, but it can affect the quantities. It is possible that a screening immunology test could test ‘positive’ as a result of the parent drug and its metabolites generating a single, combined result. The LC-MS/MS confirmation test, however, will deliver results for the drug and metabolites that are all below their respective cut-off levels.

7. pH (acidity/alkalinity)

In European drug testing guidelines, urine pH results within a range of 4 to 9 are considered normal: results lower than 3 or higher than 11 are considered to be adulterated. However, pH can be affected by foods, medical conditions and medications, so context is required in situations where it is outside the normal range.

Hair testing

8. Is it the right head?

Is the hair sample actually being taken from the right person? On the day, the trained collector should ask the donor for official photo ID, which will confirm that the test is correct and will help protect the chain of custody.

9. External contamination

Contamination can occur either through sebum or sweat, or via direct contact. It may be that the donor has been around someone smoking marijuana, or has accidentally come into contact with cocaine, which they’ve transferred from their hands to their hair. A reputable testing lab will be able to differentiate between external contamination and genuine drug use.

10. The choice of head or body hair

While head and body hair are equally accurate as markers of drug use, the two differ in terms of the timeframe of drug use that they cover. Because of the biology of body hair, it cannot be used for sectional analysis like head hair can.

11. The sample that is collected

The length of the hair that is collected will determine the timeframe for the analysis. With head hair growing at a rate of 1cm per month, each centimetre will represent a month’s history of drug use or non-use. A 3cm length of hair, therefore, will be no good if the last four months of a donor’s history are being investigated.

12. Hair colour

Research has shown that both external and ingested drugs bind well to eumelanin: a compound that is found in higher concentrations in black hair. This makes it more likely that drugs will be detected in black hair at low use but will not result in a testing bias: the rates of detection in black and blonde hair are not significantly different, even though the amount found can be.

13. Hair products or treatments

Bleach and other hair treatments can significantly reduce the percentage of drug metabolites retained by the hair. Just one treatment may leave traces of the drug, but regular treatments may destroy the metabolites altogether – meaning body hair must be used for testing.

Oral fluid testing

14. Recent drug use

The detection window for oral fluid testing is 0-2 days, meaning it is only suitable for testing “in the moment”. This means that a donor could, in theory, simply stop using a drug a few days before the test to ensure a positive result, and continue to take the drug after the test is over.

15. Screening vs. confirmation testing

A screening (immunoassay) test may give a positive result – but this positive simply means that the sample should be sent to the lab for confirmation (LC-MS/MS) tests. It may be that the LC-MS/MS then reveals a negative result: the screening could be positive purely because of the shape of the molecule of an innocuous substance similar to the drug, or because the levels of the drug found are below the cut-off levels. As an example, some codeine-based over the counter pain medications may give a positive screening result for opiates.

16. pH (acidity/alkalinity)

The pH of a donor’s oral fluid can affect the proportion of various drugs that will be ionised, and therefore that will be detectable. One study showed that increasing production of oral fluid by chewing citric acid candy, chewing gum or some other agent could, for example, “lower concentrations of codeine by about two- to six-fold.

Nail testing

17. Fingernails vs. toenails

As toenails grow more slowly than fingernails, a toenail sample will be able to reveal whether a drug has been used in roughly the previous twelve months. As fingernails grow slower, analysis of a fingernail sample will only be able to show use in roughly the last six months.

18. Incorporation directions

The keratin in nails grows in two directions: both in length, as fingernails grow from the root, and thickness, with keratin being added to the underside of the nail as it grows.

19. Drug incorporation rates

Different drugs are incorporated into both fingernails and toenails at different rates – and these rates differ from the rate of incorporation into hair. A qualified laboratory will take these differing rates into consideration when analysing results.

Leave a Reply

Your email address will not be published. Required fields are marked *

TheSuperHealthyFood © Copyright 2022. All rights reserved.