Table of ContentsView AllTable of ContentsTimelineFaster KetosisKetosis SignsSafety
Table of ContentsView All
View All
Table of Contents
Timeline
Faster Ketosis
Ketosis Signs
Safety
Ketosis is a metabolic state in which your body uses ketone bodies—compounds produced from the breakdown of fat in the liver—as its primary energy source instead of glucose (sugar). Getting into ketosis takes two to four days, on average.
A ketogenic orketo dietconsists of high fat, moderate protein, and very low carbs. People adhering to a strictketo dieteat fewer than 50 grams (g) of carbs per day. To enter ketosis, roughly 70%–80% of daily calories should come from fat, less than 10% from protein, and only about 5% fromcarbohydrates(“carbs).“Intermittent fasting before starting a keto diet can help speed up the process of getting into ketosis.
Jasmin Merdan / Getty Images
Timeline for Entering Ketosis
The human body’smetabolismuses glucose for energy (glycolysis) before it uses fat. Therefore, sugar molecules from carbohydrates that are stored in the body asglycogenmust be depleted before ketosis starts. Without stored glycogen (sugar) to burn as fuel, your body entersketosisas it gradually switches from using glucose for energy to using fat as fuel.
There isn’t a one-size-fits-all formula for determining exactly how many daily carbs make the difference between entering ketosis or not. That said, eating fewer than 50 grams of carbs a day is generally considered a ketone-producing diet.
Fullketo-adaptation, in which your body makes fat its preferred source of fuel during physical activity, can take a few weeks or even months.
The ketosis timeline can vary greatly depending on various factors, such as:
Certain illnesses that affect the thyroid (hypothyroidism) can slow metabolism and influence how long it takes to get into ketosis. Ketogenic diets may induce a shift in how the thyroid functions.
Older adults and people with health issues that slow their metabolic rate typically take longer to get into ketosis.Always speak to a healthcare provider before starting a ketogenic diet, especially if you have underlying medical conditions.
The precise timeline for fat loss on a keto diet varies from person to person.
During the first 24-hour window and the next few days on a keto diet, most weight loss is from water, not fat. Hypothetically, ketosis-induced fat loss kicks in when the body starts burning fat deposits for energy.
There is mixed evidence and ongoing debate about the fat-burning superiority of keto diets compared to other weight loss plans.
Getting into ketosis and losing weight on a ketogenic diet is a complex metabolic process; more research is needed to fully understand how it works.
Seeing a NutritionistIf you’re thinking about starting a regimented keto diet at home, talk with a healthcare provider and consult with aregistered dietitian(RD) orregistered dietitian nutritionist(RDN) before going on a dayslong fast or making radical changes to the amount of carbs, fats, or protein you’re eating every day.
Seeing a Nutritionist
If you’re thinking about starting a regimented keto diet at home, talk with a healthcare provider and consult with aregistered dietitian(RD) orregistered dietitian nutritionist(RDN) before going on a dayslong fast or making radical changes to the amount of carbs, fats, or protein you’re eating every day.
Can You Reach Ketosis Faster?
Several strategies may help you get into ketosis faster:
Signs You’re in Ketosis
Signs of ketosis range fromflu-like symptomsto “keto breath.”
The easiest science-based way to know if you’re in ketosis is a simple home test using a ketone urine strip. Any color (from pink to purple) on the ketone test strip indicates ketosis.
Symptoms of carbohydrate withdrawal that may be signs you’re entering ketosis include:
It’s difficult to answer whether ketosis is dangerous with scientific certainty. Most studies on the safety of ketosis and keto diets are of low quality and don’t have large sample sizes.
Along with a lack of sufficient high-quality clinical evidence showing keto diets are safe, there are ongoing debates about whether the benefits of keto diets that are high in unhealthy fats outweigh their risks.
In general, current research shows that being on a strict keto diet and in ketosis for about eight to 12 weeks is safe.
After 12 weeks, potential risks and possible dangers tend to increase. Although this topic remains controversial, accumulating evidence suggests that for most people, thelong-term health risksof keto diets outweigh the advantages.
Long-term adverse effects of being in ketosis for extended periods may include:
Research suggests that eating a low-carbohydrate ketogenic dietduring pregnancyincreases the risk of neural tube defects in newborns, even when taking folic acid supplements.
Ketogenic diets are usually high in red meat, processed meats, and saturated fats, which are associated with an increased risk of chronic kidney disease, heart disease,atherosclerosis(plaque buildup in arteries), cancer, diabetes, Alzheimer’s disease, and other illnesses.
Additionally, keto diets are low in health-protective foods such as fruits, vegetables, legumes, and whole grains.
Summary
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