Skip to content

Sardine Fasting

  • Sardine fasting combines fasting with preservation of essential nutrients
  • Sardines provide protein, omega-3, B12, vitamin D, calcium, and selenium
  • Rapidly induces deep ketosis with stable energy
  • FGF-21 increases, which enhances fat burning and protects muscle mass
  • Simple, safe, and flexibly applicable

Sardine fasting is a strategic fasting protocol where only sardines with skin and bones are eaten.

It combines the benefits of classic fasting:

  • Ketosis
  • Autophagy
  • Improvement of metabolic flexibility

…with preservation of essential nutrients. This reduces risks such as muscle breakdown because high-quality proteins and omega-3 fatty acids continue to be supplied.


Sardines are among the most nutrient-rich foods:

NutrientFunction
Complete proteinsMuscle preservation
Omega-3 (EPA/DHA)Inflammation reduction
Coenzyme Q10Mitochondrial function
CreatineEnergy for muscles and brain
Vitamin B12Nerve function, methylation
Vitamin DImmune system, bones
CalciumBones (from the bones)
SeleniumThyroid, antioxidant

During sardine fasting, total protein intake is relatively low but of high quality.

This causes Fibroblast Growth Factor 21 (FGF-21) to rise, a hormone that:

  • Increases fat burning
  • Stimulates metabolism
  • Helps preserve muscle mass

Sardine fasting rapidly induces deep ketosis. This provides:

  • Stable energy
  • Mental clarity
  • Reduction of inflammation

AspectRecommendation
Type of sardinesWith skin and bones, in olive oil or brine
Salt intakeAt least 3000 mg sodium per day

Approximately 1 can of sardines per 22-23 kg of body weight per day.

Example: 80 kg = approximately 3-4 cans per day.

VariantDescription
Strict3-7 days sardines only
Intermittent3 sardine days per week, 2-4 weeks
SituationalFor example, during travel

When energy is low, extra fat can be added:

  • Olive oil
  • Ghee
  • Coconut oil
  • MCT oil

  • Improved insulin sensitivity
  • Stable energy thanks to deep ketosis
  • Muscle preservation through amino acid supply and omega-3 support
  • Possible reduction in body fat
  • Better bowel movements and fewer abdominal complaints
  • Reduction of systemic inflammation

Note:

  • Adequate salt and fluid intake
  • Avoid stacking stressors (heavy training, extreme cold/heat) during longer fasting periods
  • Extended high intake may cause a slight sardine odor in some people

Veelgestelde vragen

What is sardine fasting?

Sardine fasting is a fasting protocol where only sardines with skin and bones are eaten. It combines the benefits of fasting (ketosis, autophagy) with preservation of essential nutrients and muscle mass.

How many sardines do you eat per day?

Approximately 1 can of sardines per 22-23 kg of body weight per day. Choose sardines with skin and bones, in olive oil or brine. Ensure at least 3000 mg of sodium per day.

Why sardines specifically?

Sardines are extremely nutrient-rich: complete proteins, omega-3 (EPA/DHA), coenzyme Q10, creatine, B12, vitamin D, calcium, and selenium. They support muscle preservation, inflammation reduction, and mitochondrial function.

How long can you maintain sardine fasting?

There are different variants: 3-7 days strict sardine fasting, 3 sardine days per week for 2-4 weeks, or situational sardine fasting (for example, during travel).


Medische Disclaimer: De informatie van Stichting Je Leefstijl Als Medicijn over leefstijl, ziektes en stoornissen mag niet worden opgevat als medisch advies. In geen geval adviseren wij mensen om hun bestaande behandeling te veranderen. We raden mensen met chronische aandoeningen aan om zich over hun behandeling goed door bevoegde medische professionals te laten adviseren.

Medical Disclaimer: The information provided by Stichting Je Leefstijl Als Medicijn regarding lifestyle, diseases, and disorders should not be construed as medical advice. Under no circumstances do we advise people to alter their existing treatment. We recommend that people with chronic conditions seek advice regarding their treatment from qualified medical professionals.