When following a ketogenic or “keto” diet, it’s important to eat adequate amounts of protein without going overboard. Protein is an essential macronutrient that helps maintain muscle mass, supports satiety, and aids in fat loss on keto. However, eating too much protein can actually kick you out of ketosis.
So how much protein is too much on keto? What are the potential downsides of excessive protein intake? And how can you determine your optimal protein intake for achieving your health and fitness goals?
What is the Ketogenic Diet?
The ketogenic or “keto” diet is a very low carb, high fat diet that puts your body into a metabolic state called ketosis. In ketosis, your body switches from primarily burning glucose from carbs to burning fatty acids and ketones for fuel.
Ketosis occurs when carb intake is restricted to around 50 grams or less per day. This reduction in carbs causes blood sugar and insulin levels to decrease, which signals the body to start breaking down stored body fat into ketones for energy.
Ketosis and ketones have many beneficial effects on the body and brain, including enhanced fat loss, reduced appetite, improved mental clarity and focus, stable energy levels, and more.
Why Protein Needs May Increase on Keto
Protein recommendations are higher on keto compared to a standard high-carb diet. Here are some reasons why:
- Preventing muscle loss: Lower carb intake and ketosis lead to reductions in insulin levels. Since insulin is an anabolic hormone that promotes protein synthesis, lower insulin may increase protein breakdown. Eating more protein counterbalances this effect.
- Satiety: Protein is highly satiating and helps control hunger and cravings on keto, which is lower in carb-based foods.
- Gluconeogenesis: Some amino acids from protein can be converted to glucose through a metabolic pathway called gluconeogenesis. Since keto limits carbs, higher protein intake provides another source of glucose for tissues that absolutely require it like red blood cells.
Most experts recommend consuming around 0.6-0.8 grams of protein per pound of lean body mass on keto. This equates to around 90-120 grams per day for a 150 lb person with 20% body fat.
Potential Risks of Too Much Protein on Keto
Although protein needs may increase slightly on keto, eating excessive amounts can be counterproductive for several reasons:
May Suppress Ketosis
One of the main risks of overdoing protein is that it can reduce ketone levels and suppress the state of ketosis. Here’s why:
- Stimulates insulin: Protein stimulates the release of the hormone insulin, which regulates blood sugar levels and signals the body to store fat. High protein intake can spike insulin over the level needed for ketosis.
- Excess glucose production: Protein contains amino acids like glutamine and alanine that are converted to glucose via gluconeogenesis. Too much glucose from protein can also affect ketosis.
To maintain ketosis, aim to stay within the recommended protein range based on your body weight and activity levels.
Kicked Out of Ketosis
Getting kicked out of ketosis can cause side effects like low energy, cravings, poor mental clarity, and reduced motivation to stick with the diet. Ensuring adequate but not excessive protein intake helps avoid this.
May Stall Weight Loss
One of the main benefits of keto is enhanced fat burning for weight loss. However, excessive protein intake can stall weight loss in a few different ways:
- Converts to glucose: Protein that converts to glucose via gluconeogenesis provides calories and contributes to carbohydrate intake, which may slow fat loss.
- Stimulates insulin: The insulin spike from high protein intake directs the body to store fat instead of burning it.
- Satiety: High protein is very filling. While satiety is good, it can cause too large of a calorie deficit and reduce metabolism.
To keep weight loss on track, consume protein within your target intake range based on lean body mass.
Potentially Tax Kidney Function
For most healthy individuals, moderate to high protein intakes are safe and do not damage kidney function. However, those with existing kidney issues may need to restrict protein.
When protein is metabolized, it generates metabolic byproducts like urea that must be excreted by the kidneys. High protein diets increase urea production, causing the kidneys to work harder.
For those with healthy kidneys, this is not an issue. But those with chronic kidney disease may benefit from lowering protein intake to prevent further kidney damage.
How Much Protein is Optimal on Keto?
So how much protein should you aim for on keto? Recommendations typically range from 0.6 – 0.8 grams per pound of lean body mass. To calculate your target:
- Estimate your body fat percentage – this can be done via calculator, scale, or comparison photos
- Subtract your body fat percentage from 100% to determine lean body mass
- Multiply lean body mass in pounds by 0.6 – 0.8 grams to determine protein grams
For example, a 150 lb person with 20% body fat would have 120 lbs of lean mass. Their protein recommendation would be:
- 120 lbs lean mass x 0.6 g protein/lb = 72 g protein
- 120 lbs lean mass x 0.8 g protein/lb = 96 g protein
This would equate to a daily protein intake of around 72-96 grams. Active individuals or athletes may aim for the higher end of the range.
Key Takeaways:
- 0.6 – 0.8 grams per pound of lean body mass is a good target
- Spread protein intake evenly throughout the day
- Include a protein source with each meal
- Lean meats, eggs, fish, and high protein dairy are great options
- Stay hydrated to support kidney function when increasing protein
Signs You May be Consuming Excessive Protein
Here are some signs you may be overdoing protein intake on your keto diet:
Reduced Ketones
Check your blood or breath ketones 2-3 hours after eating a high protein meal. Lower than expected ketone levels may indicate too much protein is suppressing ketosis.
Increased Hunger
Protein is satiating, so excessive hunger between meals could mean you need to increase protein at those meals.
High Insulin Levels
Monitor your blood sugar and insulin levels, especially after high protein meals. Spikes may indicate you need to better balance protein with fat and non-starchy veggies.
Fat Loss Plateaus
Stalled weight and fat loss even in a calorie deficit may be a sign you need to reduce protein and increase healthy fats to re-boost fat burning.
Changes in Kidney Markers
Get blood work done occasionally to check kidney function markers like creatinine and BUN. Increases may indicate kidney stress if protein intake is very high.
Dehydration
Increased thirst and dark urine signal inadequate hydration, which is important on high protein diets to support kidneys.
How to Determine Your Carb Tolerance
Each person has a threshold level of daily carb intake that will maintain ketosis. You can find your personal carb tolerance by gradually increasing net carbs by 5-10 grams per day until ketones drop.
To test:
- Pick a baseline of net carbs per day, around 25-30 grams.
- Check ketones in the morning and evening for 3 days.
- Increase carbs by 5 grams and repeat testing for 3 days.
- Keep slowly increasing carbs while testing ketones until they significantly drop.
- Reduce to 5-10 grams below this level to allow a buffer.
Spread these carb grams throughout the day focusing on pre-workout for energy and post-workout for recovery. You may be able to add more carbs on training days versus rest days.
Sample Higher Protein Keto Day
Here is an example higher protein keto day with around 0.7 grams of protein per pound of lean body mass along with moderate fat and low carbs:
Breakfast:
- 3 eggs scrambled with 1 oz cheddar cheese
- 2 turkey sausage links
- 1/2 avocado
Lunch:
- 4-6 oz grilled chicken breast
- 1 cup roasted broccoli
- 2 tbsp ranch dressing
Dinner:
- 6 oz salmon
- 1.5 cups sautéed spinach
- 1 tbsp olive oil
Snacks:
- 1 serving nut butter
- 1 oz pecans
- Protein shake with almond milk and cocoa powder
Conclusion
Finding your optimal protein intake on keto requires some trial and error. Consuming too little can lead to muscle loss, hunger, and poor metabolism. But excessive amounts may also reduce ketosis, stall fat loss, and in rare cases harm kidney function.
Aim for 0.6-0.8 grams per pound of lean mass or around 90-120 grams per day for most individuals. Spread this evenly throughout your meals and pair it with healthy fats and non-starchy vegetables. Monitor your symptoms and make adjustments as needed based on your goals.
