Nutrition test: The types available and what they really measure

What to expect in this article

1. What is a nutrition test?
2. Why is a test result an indication rather than proof?
3. What types of nutrition tests are there?
4. What applies regardless of any test result?
5. What exactly does each nutrition test measure?
6. Which nutrition test is right for which question?
7. How do you evaluate the results of a nutrition test?
8. What can’t a nutrition test do?
9. What misconceptions persist about nutrition tests?
10. How does mybody® conduct a genetic nutrition test?
Conclusion
Frequently asked questions
Sources

What is a nutrition test?

A nutrition test is an examination procedure that collects information about how a body processes food—through a bodily sample, a measured response, or the systematic observation of eating behavior. The term therefore describes not one specific method, but an entire group of very different procedures.

That is precisely where the most common disappointment lies: Depending on the provider, someone who buys “a nutrition test” may receive a genetic analysis, an antibody measurement, a nutrient analysis, or an evaluation of their own food diary. These four things answer completely different questions.

“Food test” is not a protected technical term

Unlike, for example, the hydrogen breath test used when lactose intolerance is suspected, “food test” is not a defined medical examination but a market term. That is why a product’s name says almost nothing about what is actually measured.

The practical consequence: Before buying any test, the first question is not “Is this test good?” but “What sample is collected, and what is measured in it?” Only this answer reveals which question the test can actually answer.

What a food test can examine: predisposition, state, or reaction

Practically all methods can be assigned to three categories. Genetic tests examine a predisposition—that is, variants in DNA that do not change over the course of a person’s life. Blood and nutrient analyses examine a state that can shift from week to week. Functional and provocation tests examine the body’s reaction to a defined stimulus.

Observation methods such as a food and symptom diary form a fourth, often underestimated group. According to the Institute for Quality and Efficiency in Health Care (IQWiG, 2023), for persistent symptoms it may be useful to “record them in a food and symptom diary for several days to several weeks.”

Where this article fits—and where to continue reading

This article provides the foundations: it maps out the field and explains the logic behind the different methods. If you are instead interested in the practical process of taking a test at home—ordering, collecting the sample, shipping, and receiving the results—the article is Online food intolerance test is the right choice. If you are specifically concerned about intolerances and allergies, Food intolerance test for a deeper look at diagnostics.

Why is a test result an indication and not proof?

A test result always describes a measurement, not a disease. Between the measured value and the symptom that led you to take the test lies an interpretation—and that interpretation can be wrong in either direction.

This can be demonstrated most clearly using a procedure for which an official assessment is available: the blood test for IgE antibodies, which is used when an allergy is suspected. According to IQWiG (2024), this test “measures the number of certain antibodies—namely IgE antibodies—in the blood sample in the laboratory […]”.

The IQWiG writes about precisely this blood test for IgE antibodies—and explicitly only about this test—in its guide to allergy tests:

IQWiG explains this assessment in the same section: “This means that there may also be more IgE antibodies in the blood without an allergy, for example in people who smoke or have a parasitic infection.” An elevated value is therefore a reason to look more closely—not an answer.

The same source also describes what happens next: “A provocation test is only useful once the skin test or a blood test has not produced clear results” (IQWiG, 2024). The laboratory test is therefore not at the end of the diagnostic process, but in the middle of it.

Our editorial assessment: The idea extends further

The IQWiG quotation refers exclusively to the blood test for IgE antibodies. The following generalization is our own editorial assessment by the mybody® editorial and medical expert team and is not a statement by IQWiG.

From our perspective, this sentence describes the basic principle of every nutrition test: A measurement in the laboratory captures one aspect, not the whole picture. This applies to genetic variants as well as blood values and breath-gas measurements—just for different reasons in each case.

Once you have internalized this sentence, you read every test result differently. An abnormal value then becomes a question for the next examination, not a reason to eliminate a food forever.

What types of nutrition tests are there?

Nutrition tests can be divided into four families: genetic tests from saliva, blood tests for antibodies and nutrients, functional tests such as the hydrogen breath test, and observational methods such as a food diary and elimination diet. Each family has its own area of application.

The breadth of the third and fourth families alone in everyday medical practice is illustrated by the IQWiG guide to allergy tests. Depending on the question, it lists the skin prick test, intradermal test, scratch test, rub test, patch test, blood test, and challenge test as procedures that may be used (IQWiG, 2024).

What is strikingly absent from this list is a genetic test. The IQWiG page on the causes and diagnosis of lactose intolerance (2024) also lists the hydrogen breath test, the lactose tolerance test, and the elimination test as diagnostic procedures—but no genetic test.

This leads to a clear division of roles: genetic tests provide context about predisposition, while medical functional and challenge tests provide the diagnosis. A reputable provider states this clearly, not the other way around.

What applies regardless of any test result?

The reference values of the German Nutrition Society (DGE) apply to all adults—regardless of whether they have ever taken a nutrition test. No test result overrides them, and no test result makes them unnecessary.

Source: German Nutrition Society (DGE), reference values

Why these three figures are the real benchmark

The DGE protein reference value (2025) is approximately 57 grams per day for men and approximately 48 grams per day for women aged 19 to 65. From age 65 onward, the estimate increases to 1.0 grams per kilogram of body weight.

For fat, the DGE gives a reference value of 30 percent of total energy for adults between 19 and 65 years of age. This establishes the framework for the three macronutrients before any test even comes into play.

Energy requirements are also well documented. For people aged 25 to under 51, the DGE reference values at PAL levels of 1.4, 1.6, and 1.8 are 2,300, 2,700, and 3,000 kilocalories per day for men and 1,800, 2,100, and 2,400 kilocalories per day for women, respectively.

This also includes the physical activity that factors into every nutritional calculation. The World Health Organization (WHO, 2020) recommends that adults engage in 150 to 300 minutes of moderate-intensity or 75 to 150 minutes of vigorous-intensity aerobic activity per week, as well as muscle-strengthening activities on at least two days.

These values provide the context against which every test result must be interpreted. A test can explain why changing your diet is easier or harder for you—but it cannot explain why 30 grams of fiber a day would suddenly no longer be appropriate.

What exactly does each nutrition test measure?

Each of the common methods measures exactly one parameter. This chapter examines the most important ones in order and explains what each can do and where its limits lie.

DNA test from saliva: the predisposition

A DNA test examines genetic variants obtained from a saliva sample. Because the DNA sequence remains stable throughout life, the result is valid once and does not need to be repeated.

Genetic predispositions are indeed relevant to food-related issues. IQWiG (2024) explains that, in some people, the body “then no longer produces enough lactase” “to break down the lactose consumed through food”—this is referred to as “inherited or primary lactase deficiency.”

Nevertheless, a DNA test does not replace diagnostic testing. The symptoms may also have a secondary cause: According to IQWiG (2024), lactase deficiency can develop when “an intestinal disease impairs the production of lactase,” for example in celiac disease or Crohn’s disease. A genetic test cannot detect such a cause.

Blood test for IgE antibodies: an indication of allergy

A blood test for a food allergy checks “whether the body has produced certain antibodies (usually IgE antibodies) against a food” (IQWiG, 2023). In other words, it measures the amount of a specific class of antibodies.

The finding is one part of the diagnostic process, not its conclusion. According to IQWiG (2023), diagnosing a food allergy “usually requires a provocation test, in which small amounts of the suspected food are consumed under medical supervision.”

IgG and IgG4 tests for foods: IQWiG’s clear assessment

In addition to IgE tests, blood tests for IgG and IgG4 antibodies against foods are offered, and they regularly appear in search results for the term nutrition test. IQWiG explicitly assesses this type of testing: Such tests are “currently not recommended” “because they are not very informative” (IQWiG, 2023). This assessment belongs in any honest overview of nutrition tests—even when a provider includes such tests in its range.

Hydrogen breath test and lactose tolerance test: how they work

According to IQWiG (2024), a hydrogen breath test measures “how much hydrogen the exhaled air contains—both before and after drinking a lactose solution.” The test therefore reflects what actually happens in the digestive tract.

The same source mentions the lactose tolerance test as an alternative: “In this test, blood sugar levels are measured before and several times after drinking a lactose solution” (IQWiG, 2024). Both methods should be performed under medical supervision.

The prevalence of the issue is illustrated by a figure from the same source: According to IQWiG (2024), around 5 to 15 percent of people in Europe cannot tolerate lactose, while in Africa or East Asia, 65 to over 90 percent of adults are affected.

Diary, elimination diet, and food challenge test: observation

The least expensive method costs nothing except attention. During an elimination diet, according to IQWiG (2023), “suspected foods are avoided for 1 to 4 weeks, and changes in symptoms are recorded in a food diary.”

When lactose intolerance is suspected, IQWiG (2024) describes avoiding lactose-containing products for around four weeks, followed by a challenge test. Here too, only controlled reintroduction provides reliable information.

Which dietary test is suitable for which question?

The three most common sample-based methods—DNA testing from saliva, blood testing for IgE antibodies, and the hydrogen breath test—differ in every single respect. The following overview compares them using identical criteria.

The table makes clear why the question “Which nutrition test is the right one?” cannot be answered without additional information. Only the specific question determines which procedure should even be considered.

For acute symptoms after eating, the path leads to medical evaluation and the established procedures used there. When the question is how your own metabolism is predisposed, a genetic test provides context—but not a diagnosis.

How do you evaluate the result of a nutrition test?

A test result is evaluated meaningfully by checking it against three things: your actual symptoms, the question the test can answer, and the general reference values. Without this comparison, a report remains merely a collection of numbers.

The most common evaluation error is jumping straight from an abnormal result to a conclusion. A highlighted entry in the report initially means only that a measured value falls outside a reference range—not that a particular food causes symptoms.

The second typical mistake is quietly compiling a list of foods to eliminate. Anyone who avoids several food groups at the same time after receiving a finding loses the ability to identify the connection at all—and risks an unnecessarily unbalanced diet.

That is why the structured approach is the same as in diagnosis: one hypothesis, one period, one observation. IQWiG (2023) describes exactly this framework for an elimination diet, with 1 to 4 weeks of avoidance accompanied by a food diary.

Anyone who works through these five questions will almost always arrive at a calmer conclusion than they did at first glance at the findings. That is not a disadvantage—it is the real benefit of a proper evaluation.

What can’t a nutrition test do?

No nutrition test replaces a medical diagnosis, none predicts weight-loss success, and none changes the body’s nutrient requirements. A nutrition test does not change what your body needs—it only changes what you know about it.

The evidence for personalized nutrition is sobering.

In a separate statement in 2022, the German Nutrition Society assessed the benefits of individualized nutrition services. Although scientific studies indicate moderate effects from increased motivation, analyses involving individualization—such as genetic and blood analyses or microbiome data—have generally not produced statistically significant improvements in eating behavior (DGE, 2022).

The same DGE statement describes the effectiveness of personalized nutrition as disappointing so far—and this despite the fact that corresponding services have been commercially available for more than 20 years. This assessment belongs in every honest article on the subject.

A 2025 DGE blog post also reports that researchers found “that tests offer no added value for people who, for example, want to lose weight.” To put genetic tests into context, it reproduces an individual expert opinion—not an institutional position of the DGE—according to which such tests are “from a scientific perspective […] unnecessary for weight-loss recommendations.”

What this means for your expectations

A nutrition test is therefore neither a weight-loss tool nor a diagnostic device. It can make connections visible, provide structure for discussions with specialists, and focus your attention on specific issues.

What it cannot do is the work that follows. Putting the results into practice in everyday life—shopping, preparation, exercise, and sleep—remains the part that determines the outcome, and there is no shortcut through a sample.

And finally, the boundary that was there at the beginning remains: Even a technically flawless test provides only an indication. Whether that indication applies in your case becomes clear only through observation and—where medically necessary—medical evaluation.

What misconceptions persist about nutrition tests?

Two assumptions come up particularly often in connection with nutrition tests. Both sound plausible, and neither stands up to the available evidence.

The first misconception arises from the language of the results: A highlighted value appears like a verdict. In reality, it merely describes a deviation whose significance only emerges in conjunction with the symptoms.

The second misconception concerns quantity. The number of markers analyzed says nothing about the significance of any individual marker—and even less about whether dietary behavior will ultimately change.

A third, unspoken misconception is rarely voiced: that a test makes the decision for you. It provides information; deciding what follows remains up to you and—in medical matters—to your doctor.

How does mybody® implement a genetic nutrition test?

mybody® (MYBODY Lab GmbH) offers the NutriCare | INFINITY, a genetic nutrition test that explicitly belongs to the first of the four procedure families: It examines variants in DNA from a saliva sample and thus describes a predisposition.

The analysis is carried out in an ISO-certified laboratory in Germany, the data transfer is SSL-encrypted, and processing complies with the GDPR. Samples are processed pseudonymously; the saliva sample and DNA sequence are destroyed two months after the analysis.

NutriCare | INFINITY DNA test

The NutriCare | INFINITY evaluates more than 140 genetic variations and provides 54 analysis reports in 8 chapters spanning around 200 pages, along with a food table containing more than 1,000 analyzed foods. The mybody® Metabolism Type chapter contains four reports on alcohol metabolism, caffeine metabolism, lactose metabolism, and gluten intolerance. Important context: The test describes genetic predispositions and does not provide a diagnosis. It neither detects lactose intolerance nor an allergy, does not replace a hydrogen breath test or a challenge test, and does not predict weight-loss success.

Price: €269.00  ·  Sample type: Saliva sample  ·  Processing time: approx. 20–25 business days after receipt by the laboratory  ·  Laboratory: ISO 27001-certified laboratory analysis

About NutriCare | INFINITY

For the four reports mentioned in the mybody® Metabolic Type chapter, the connection to the topic of tolerance is verifiable. This does not apply to other questions of food tolerance—medical diagnostics remain responsible for those.

To be equally clear: mybody® does not offer a standalone test product for lactose or fructose intolerance. The hydrogen breath test remains the procedure that answers the medical question here.

All prices and service details are current as of August 3, 2026. Prices and processing times may change; the respective product page is always authoritative.

Conclusion

A nutrition test is not a standardized product but a collective term for four families of procedures: genetic tests using saliva, blood tests for antibodies and nutrients, functional tests such as the hydrogen breath test, and observational methods such as a diary and elimination diet.

The most important statement on the subject comes from IQWiG (2024) and applies there to blood testing for IgE antibodies: The test is an indication, not proof. We consider this idea editorially transferable—every test result is just one part of the picture, and only its interpretation makes it useful.

Specifically, before buying, clarify which sample will be taken and what will be measured. Acute or persistent symptoms after eating should be evaluated by a doctor; the established procedures used there—skin, blood, challenge, and breath tests—cannot be replaced by anything else.

Regardless of any test result, the basics remain the same: 30 grams of fiber per day, 0.8 grams of protein per kilogram of body weight for adults aged 19 to 65, and more than 50 percent of energy intake from carbohydrates as part of a balanced mixed diet (DGE).

Frequently asked questions

Sources

1. IQWiG / gesundheitsinformation.de: What allergy tests are available? (2024) — gesundheitsinformation.de
2. IQWiG / gesundheitsinformation.de: Food allergy – diagnosis and treatment (2023) — gesundheitsinformation.de
3. IQWiG / gesundheitsinformation.de: Causes and diagnosis of lactose intolerance (2024) — gesundheitsinformation.de
4. German Nutrition Society (DGE): Statement “Rethinking Personalized Nutrition” (2022) — dge.de
5. German Nutrition Society (DGE): Reference values for fiber (2021) — dge.de
6. German Nutrition Society (DGE): Reference values for protein (2025) — dge.de

The quotation regarding the significance of blood testing for IgE antibodies, the list of allergy testing methods, and the assessment of the challenge test are based on [1]. The information on blood tests, elimination diets, challenge tests, and the assessment of IgG and IgG4 tests is taken from [2]. The descriptions of hydrogen breath tests, lactose tolerance tests, elimination tests, primary and secondary lactase deficiency, and the figures on the prevalence of lactose intolerance are based on [3]. The assessment of the evidence for personalized nutrition is taken from [4]. The reference values for fiber and protein are taken from [5] and [6]; the information on carbohydrates, fat, and energy comes from the corresponding DGE reference values, and the exercise recommendation comes from the 2020 WHO guidelines. Product information comes from the mybody® product pages, accessed on August 3, 2026. All other sources cited in the text are identified directly at the relevant point by institution and year.

mybody® Editorial & Expert Team

Nutrition tests Nutrigenetics Laboratory diagnostics Nutritional science

This article was written and medically reviewed by the mybody® Editorial and Expert Team. The team combines expertise in nutrigenetics, microbiome and gut science, blood analysis interpretation, nutritional science, and laboratory diagnostics.

Published on August 3, 2026 · Last updated on August 3, 2026

Medical notice: This article is intended for general information and does not replace medical advice, diagnosis, or treatment. None of the tests described here constitutes a diagnosis. If you experience severe, new, or persistent symptoms after eating, or suspect an allergy or intolerance, please consult a doctor.