Why do I feel sleepy after drinking protein shakes?

Author: Tyra Marks  |  Last update: Tuesday, October 7, 2025

Quite simply, whey protein is just very insulinogenic — meaning, it breaks down into amino acids very quickly which get quickly absorbed and then rapidly stimulate a whole lot of insulin production. This in turn lowers your blood sugar level which in turn can makes you quite sleepy/fatigued.

Can protein shakes make you sleepy?

Feeling sleepy after consuming a whey protein shake can be attributed to several factors: Digestive Process: Whey protein requires digestion, which can divert blood flow to your digestive system and may cause feelings of fatigue as your body works to process the protein.

Can too much protein make you sleepy?

The lower the fat content of a protein, the greater the insulin spike. Protein triggers the hormone glucagon, which counters insulin. When you consume a combination of protein and carbohydrates, like a burger with fries or meat and potatoes, you greatly enhance insulin. This will cause you to feel sleepy after eating.

Why do I feel weird after drinking protein shakes?

Foods and drinks that are low in fibre, carbohydrates, and healthy fats tend to be digested very quickly. Protein shakes, which are liquid, are digested even faster than that. This can cause issues with digestive enzymes in your digestive system and can lead to nausea, bloating, and an upset stomach.

What happens to your body when you start taking protein shakes?

While protein shakes provide essential protein, they lack the full range of nutrients your body needs, such as fiber, healthy fats, and micronutrients found in whole foods. This can result in fatigue, digestive issues, and muscle loss over time.

Fatigue After Eating: Why It Happens and How to Fix It

Is it bad to drink a protein shake every day?

And if you rely too much on protein shakes to replace daily meals, you'll miss out on the healthy benefits of whole foods. Since protein has calories, consuming too much can make it harder to lose weight.

How long does it take to start seeing results from protein shakes?

Depending on your starting point, it can take anywhere from a few weeks to several months to see noticeable changes in muscle mass. For those looking to lose weight or improve body composition, whey protein can be helpful as part of a calorie-controlled diet.

Are there negative effects of protein shakes?

Potential side effects of protein shakes

You might experience the following if you drink protein shakes. Gas, bloating, diarrhea, stomach cramps. This happens most often with whey protein powders. This can be related to a lactose intolerance.

What happens if you drink a protein shake on an empty stomach?

Drinking protein on empty stomach during breakfast helps set the tone for rest of the day by getting you the jumpstart on the daily protein intake. Add protein powders as a breakfast boost. Protein powders can easily be mixed into some of your go-to morning foods or beverages.

Why is my protein shake making me gain weight?

Excessive carb and fat content: Protein powders often contain other nutrients, and if not accounted for, the carbohydrate and fat content can lead to weight gain. Lack of physical activity: When energy demand is low, extra protein can be converted to glucose and eventually stored as fat.

How much protein do I need to lose weight?

If you want to lose weight, aim for a daily protein intake between 1.6 and 2.2 grams of protein per kilogram of body weight (. 73 and 1 grams per pound). Athletes and heavy exercisers should consume 2.2-3.4 grams of protein per kilogram (1-1.5 grams per pound) if aiming for weight loss.

What does a protein deficiency look like?

Common signs that your body is extremely low on protein include: Brittle hair and nails, often the first sign of deficiency. Feeling weak or hungry, since protein supplies energy and satisfies the appetite. Getting sick often without protein to boost the immune system.

Is it better to drink protein shakes in the morning or at night?

Generally speaking, consuming enough protein is more important than the exact timing of when you have it – unless you're doing resistance training, where it is recommended to have it directly before or after exercise. Taking protein before bed is also a valid option for muscle growth and exercise adaptation.

What to avoid in protein powder?

Ingredients to avoid
  • Multi-ingredient products. Some protein powders include additional nonprotein ingredients. ...
  • Sugar, sugar alcohols and other sweeteners. Many flavored protein powders contain added sugar. ...
  • Heavy metals.

How much protein do I need a day?

The recommended dietary allowance to prevent deficiency for an average sedentary adult is 0.8 grams per kilogram of body weight. For example, a person who weighs 165 pounds, or 75 kilograms, should consume 60 grams of protein per day. If you're over age 40-50.

Why do I feel sleepy after a protein shake?

When you eat protein, your body breaks it down into these tiny building blocks. But here's the catch: consuming too much protein at once can cause a blood sugar spike, leaving you feeling sluggish and, well, sleepy.

Should you chug or sip a protein shake?

The obvious answer is that you slow down and sip your shake as you would any other drink. Here are some of the reasons why chugging your protein shake might be preventing an optimal digestive experience, and what you can do to improve it.

Are protein shakes OK to drink everyday?

If you do not have any digestive problems or food sensitivities, you may be able to drink a protein shake every day. Because the protein powder in protein shakes is not regulated the way drugs and food are, the long-term side effects of drinking protein shakes are unknown.

Is 2 scoops of protein too much?

The number of scoops of protein powder you should take to gain muscle depends on your needs and goals. As a general guideline, it's recommended to consume 1-2 scoops of protein powder per day, combined with a balanced diet and exercise program, to support muscle growth and recovery.

When to drink protein shakes for weight loss female?

For those aiming to shed weight, a prime moment to enjoy a protein shake is in the morning. Protein plays a pivotal role in fat loss, and kickstarting your day with it can rev up your metabolism, maintaining its elevated state throughout the day.

What are the side effects of taking protein powder?

Excess intake of these proteins can also cause increased bowel movements, bloating, and even nausea. Other side effects include flatulence and diarrhea. If taken in excess quantities, protein supplements can cause you to gain weight. And by weight, we mean fat.

Which protein gives fast results?

Whey protein for muscle recovery: This protein powder is rich in essential amino acids and Branched Chain Amino Acids (BCAAs). This is why it helps in faster muscle recovery post-workout.

How much weight can you gain in a month with whey protein?

A: Whey protein, combined with a proper diet and weight training, can help you gain weight. With consistent training and a caloric surplus, a novice can expect to gain approximately 0.5 to 1 pound of muscle per week, which translates to 2 to 4 pounds per month.

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