Surprising to many, what we eat first can determine how our bodies react metabolically to subsequent foods.  By metabolically, I am referring to increases in blood sugar, inflammation, blood lipids and weight gain.  Multiple studies have looked at what happens metabolically if the first thing we eat is protein. 

Eating activates inflammation either significantly or mildly.  The difference is mediated by the level of insulin response.  Different meal compositions increase insulin and inflammation to different degrees with a smaller activation being healthier.  A diet with excessive carbohydrate or fat causes a much higher

insulin response, more inflammation and weight gain.  This excessive response, if done repeatedly, is termed meta-inflammation which is highly associated with belly fat gain, diabetes risk, fatty liver disease and vascular disease.

Perhaps the most impactful result from a diet high in carbohydrate or fat is simply that it is pro-inflammatory and increases belly fat and all of the related diseases over time.

These negative effects can be modified by what has been eaten previously to consume carbohydrates or fat.  Consumption of protein by itself has been found to reduce the insulin levels associated with eating carbohydrates or fat at the next meal.  Several studies have used a whey protein premeal to study this effect.(1)  This study was a meta-analysis which collects all of the data from previous studies.  The data showed that the whey premeal lowered blood glucose response after a subsequent meal of carbohydrate.  Interestingly it also increased the release of GLP-1 from the gut.  The latest drug “rage” for diabetes control and weight loss are GLP-1 agonist drugs meaning they create the effect of GLP-1.

We secrete GLP-1 in the gut normally in response to eating which signals satiety, the feeling of “I have had enough”.  Satiety is our stop eating signal. Without it, we tend to overeat.  Generally, the major stimulus to GLP-1 release during eating is pungent or bitter taste, something that is absent in most of the processed foods consumed.  Pungent and bitter taste comes from colorful fruits, vegetables and spices.  While the drugs are all the rage right now, much of the same metabolic improvement can be obtained with protein loading and a diet high in pungent and bitter tastes.

In yet another study examining this protein first metabolic strategy, researchers simply looked at eating a primarily protein meal for breakfast and looking at metabolic response to a higher carbohydrate challenge 2 hours later.(2)  The results agreed with the meta-analysis discussed above.  If the first meal is mostly protein, the negative impact of subsequent carbohydrates is minimized.

The research is clear.  Starting the day with predominantly protein helps limit insulin response, inflammation and weight gain, especially if the subsequent meals contain pungent taste and some bitter signaling.  Who would have thought?!

1. Smedegaard et al. Whey Protein Premeal Lowers Postprandial Glucose Concentrations in Adults Compared with Water—The Effect of Timing, Dose, and Metabolic Status: a Systematic Review and Meta-analysis.  The American Journal of Clinical Nutrition, 2023;118(2):391-405. 
2. Meng et al. Effect of prior meal macronutrient composition on postprandial glycemic responses and glycemic index and glycemic load value determinations.  The American Journal of Clinical Nutrition, 2017;106(5):1246-1256.