Fasting, Overeating and Illness: GAPS and Gut Flora

The GAPS books distinguish prolonged food deprivation from the nutrient-containing Liquid GAPS approach. They also describe overeating, infection, chronic illness and medical treatment as influences on gut flora. Reading those situations together helps explain why the GAPS account looks at a history of changes rather than one food or one event.^[1][2]

Gut flora means the community of microbes living in the digestive system. If that term is new, the gut-flora guide gives you the wider picture. Here, the useful question is what the books say can disturb that community and how their two fasting discussions differ.

Prolonged Fasting and Overeating in the Earlier Book

The expanded Gut and Psychology Syndrome discussion lists prolonged fasting, starvation and overeating as patterns that can seriously alter the composition of gut flora. It places too little and too much food in the same discussion, rather than treating only one extreme as relevant.^[1]

An earlier English edition also includes parenteral feeding in that list. Parenteral nutrition supplies nutrients through a vein and bypasses the gastrointestinal tract. It is different from feeding through a tube into the stomach or intestine.^[3][4]

In these passages, Campbell-McBride discusses adding beneficial bacteria in probiotic form. The observation about gut flora is a reason to consider the whole nutritional and treatment situation. It is not an instruction to interrupt medically necessary feeding.^[1][3]

Why Liquid GAPS Is a Separate Discussion

In Gut and Physiology Syndrome, Campbell-McBride describes a temporary break from solid food using clear liquids that supply minerals, vitamins, enzymes, probiotics, fats and proteins. She advises against water-only fasting in this GAPS context because she describes the body as malnourished and carrying a toxic load.^[2]

That is a different preparation from simply going without nourishment. Clear meat stock and strained vegetable broth are not the same as a bowl of soup with pieces in it. The liquid from a vegetable ferment is not the whole ferment. A blended meal can be drinkable while still containing solid matter. The drink guide explains the actual preparations.^[2]

The distinctions in the chapter matter just as much as the drink list:

• The book limits slim or underweight people, and pregnant or nursing women, to no more than one day at a time, with at least a month between episodes.
• It separately discusses early-pregnancy nausea and directs a return to Full GAPS when nausea subsides and appetite returns.
• It describes an exception for acute Crohn’s disease or ulcerative colitis when solid food cannot be managed, even if the person is underweight. That is the body-mass exception, not an extension of it to pregnancy or nursing.
• It explicitly excludes anorexia nervosa from the advice to fast when appetite is absent.

These are the chapter’s stated limits and exceptions. The situations and limits guide keeps them together; the Liquid GAPS overview explains the complete approach. The fasting passage cannot be used to tell someone with anorexia to wait for hunger before receiving nourishment.^[2]

Diet Is One Part of the History

The earlier book says that dysbiosis, its term for an unhealthy change in gut flora, is usually fairly mild when poor diet is the only cause. It then explains why diet is often not the only factor: antibiotic exposure and other influences can occur alongside it.^[1]

This does not turn the diet into an unimportant detail. It means a food history and a treatment history may both help explain the pattern being discussed. A change in eating, an infection and an antibiotic course are separate events, even when they happen close together.

Infection, Chronic Illness and Treatment

The book names typhoid, cholera, dysentery, salmonella and some viral infections as illnesses that can leave lasting damage to gut flora. It says restoring beneficial bacteria should be an important part of care after those serious infections.^[1]

It also describes serious gut-flora defects alongside diabetes, autoimmune disease, endocrine disease, obesity and neurological conditions. Endocrine disease means disease involving the body’s hormone system. Surgery, chemotherapy, hormone therapy and radiotherapy appear as further situations after which flora can be damaged.^[1]

Those are different kinds of influence: a food pattern, an illness and a treatment are not interchangeable. A microbiome explanation does not establish which caused an individual symptom or tell you to change a prescribed treatment. The antibiotic-recovery guide covers that related history in more detail.

Make the Pattern Easier to Describe

If you are putting together a history, use dates and concrete changes. For example, keep “eating became difficult,” “infection diagnosed,” “antibiotic course started” and “abdominal symptoms appeared” in separate entries. These are examples of the kinds of events to record, not a suggested sequence that every person follows.

Describe the actual change in food as well: less food overall, fewer accepted foods, a prescribed feeding preparation, or a planned change in the form of meals. That is more useful than writing only “the diet changed.” Keep the record alongside the care plan rather than using the history to decide on a fast.

Frequently Asked Questions

Does Mentioning Fasting Mean the Two Books Contradict Each Other?

They discuss different situations. The earlier passage names prolonged deprivation among influences that can damage flora. The 2020 chapter describes a specific nutrient-containing, no-solids approach with its own conditions. The shared word “fasting” does not make the preparations identical.^[1][2]

Does the Book Say Diet Is Always the Only Cause?

No. Its discussion explicitly recognizes overlapping influences, including drugs and infections. A history can contain more than one contributor.^[1]

Does Its Appetite-Led Fasting Advice Apply to Anorexia?

No. The 2020 book specifically excludes anorexia nervosa from that advice. The refeeding and digestion guide explains the separate eating-disorders discussion.^[2]

Your Next Step

Start with the gut-flora overview if you need the basic explanation. If you are reading about the kitchen preparation for Liquid GAPS, continue with the named drinks and the full situations and limits discussion. My Liquid GAPS Recipe Collection is listed in the shop for that preparation work.

References

1. Campbell-McBride, Natasha. Gut and Psychology Syndrome, expanded text represented by the second German edition (2015), “Welche anderen Faktoren können sich auf die Darmflora auswirken?” (“What Other Factors Can Affect Gut Flora?”), diet, disease and overlapping influences. English paraphrases checked against that text; no English page number is implied.
2. Campbell-McBride, Natasha. Gut and Physiology Syndrome (2020), “GAPS Liquid Fasting,” nutrient-containing liquids, water-only fasting, underweight/pregnancy/nursing limits, acute inflammatory-bowel exception and anorexia-nervosa exclusion.
3. Campbell-McBride, Natasha. Gut and Psychology Syndrome, earlier English edition, “What Can Damage Gut Flora?”, diet and disease discussion, including parenteral feeding.
4. MedlinePlus Medical Encyclopedia. Total Parenteral Nutrition, feeding through a vein and bypassing the gastrointestinal tract.