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Integrative Health

Protein Or Fiber For Breakfast? New Research Has An Answer

Ava Durgin
Author:
Ava Durgin
February 24, 2026
Ava Durgin
Assistant Health Editor
By Ava Durgin
Image by Kayla Snell / Stocksy
February 24, 2026

We've all heard it a thousand times. Breakfast is the most important meal of the day. 

For years, nutrition advice has swung between “never skip breakfast” and “just fast until noon.” Somewhere in between, most of us just got confused. 

But a new study 1published in the British Journal of Nutrition is bringing breakfast back into the conversation, and this time, the research asks something more specific than just whether you should eat it. Does front-loading your calories earlier in the day drive weight loss, and does the type of breakfast you eat change the outcome?

A look into the study

This randomized trial recruited 19 adults with overweight or obesity and put them through two different 28-day eating plans in sequence. Both plans had the same calorie distribution:

  • 45% of daily calories at breakfast
  • Up to 35% at lunch
  • 20% in the evening

The difference was in breakfast composition. One group followed a high-protein plan (30% protein, 35% carbs, 35% fat, with fiber capped at 15g/day). The other followed a high-fiber plan (50% carbs, 15% protein, 35% fat, with at least 30g of fiber daily). 

Participants then crossed over to the opposite plan, so researchers could compare results within the same individuals.

High-protein vs. high-fiber breakfast

Here's where it gets interesting. Both groups lost weight, and meaningfully so:

  • The high-fiber group lost an average of 10.7 lbs over 28 days
  • The high-protein group lost an average of 8.5 lbs
  • Both diets also lowered blood pressure and blood lipids

But the benefits diverged from there. 

The high-fiber breakfast significantly increased gut microbiome diversity, including a boost in butyrate-producing bacteria like Faecalibacterium and Roseburia, the kind linked to intestinal health and reduced inflammation. 

The high-protein breakfast, on the other hand, suppressed appetite more effectively, which could be the real advantage for people who struggle with cravings and overeating throughout the day.

These findings suggest that shifting more calories earlier in the day may be beneficial for weight loss, and both protein and fiber offer unique advantages.

You don't have to choose one or the other

You don't have to pick between protein and fiber. (Read that again!) You can absolutely build a breakfast that delivers both.

Here are a few simple examples:

  • Eggs + vegetables + avocado: Two scrambled eggs (plus egg whites if you want to bump up the protein) with sautéed spinach and a side of avocado gives you protein, fiber, and gut-loving prebiotics in one bowl.
  • Greek yogurt parfait: High-protein Greek yogurt layered with raspberries, chia seeds, and a sprinkle of hemp hearts. Check out this RD-approved yogurt bowl.
  • Chia seed pudding: This high-protein raspberry chia mousse packs 40 grams of protein and 16 grams of fiber. 
  • Protein smoothie with greens and berries: This strawberry vanilla smoothie tastes like dessert and has a whopping 26 grams of fiber.

The takeaway

Eating more of your calories earlier in the day appears to be a useful strategy for weight loss and metabolic health. Protein keeps hunger in check while fiber feeds your gut. 

And this isn’t an either-or situation.

You can build a breakfast that includes both. Pairing high-quality protein with fiber-rich whole foods can help you stay full longer, keep your energy steady, and support both your gut and your metabolic health at the same time.