🫘 The ‘subsequent meal effect’

A variety of things can affect blood sugar levels after a meal that have nothing to do with what the food eaten at that meal.

An example is the ‘subsequent meal effect’.

This is a physiological response whereby the food eaten influences the blood sugar levels at the next meal by a significant amount.

Research shows that this phenomenon mostly occurs with wholegrains, legumes and other high-fibre foods.

For example, inclusion of whole grains or legumes at breakfast decreases blood sugar levels at lunch and/or dinner on the same day.

Or, consumption of dinner rich in whole grain or lentils reduces blood sugar levels at breakfast the following morning.

However, this effect is lost when the food is modified through processing, such as milling, processing, and cooking at high temperatures.

🥊 Summary

The ‘subsequent meal effect’ has important implications for the control of blood sugar levels across the day, especially for those at risk of diabetes.

🍝 Going low-carb for some time

How the body handles sugar after periods of carbohydrate restriction can also affect blood sugar levels.

Going low-carb for a long time can induce physiological changes, such as a likely reduction in insulin synthesis and secretion (some kind of insulin resistance).

This means that when that person next eats some carbs, their blood sugar response will likely be exaggerated.

This phenomenon has been known since the 60s

This is why an oral glucose tolerance test (a test to assess how well you body clear sugar from the blood) should be done after consuming carbs for at least 3 days before the test.

Healthy males and females who take an oral glucose tolerance test after 5 days of very low carb intake of 20g carbs per day show up (falsely) as having impaired glucose tolerance.

This phenomenon can give people real anxiety and a fear that they can’t tolerate carbs and should always avoid them.

🥊 Summary

Going low carb for long can change how the body response to glucose after eating high carb foods. This doesn’t mean that once started, you’ll always be on a low carb diet. With enough time, the body can adapt to different fuel sources.

🏋️‍♀️ Exercise days or hours before the meal

Most people know that regular physical activity can improve insulin sensitivity and reduce the risk of type 2 diabetes.

What people might not know is that a single bout of exercise can affect glucose levels.

The glucose response to a food will be higher if eaten immediately after a bout of intense exercise, versus after rest.

This effect could last up to 1 hour, but once the post-exercise period is over, insulin sensitivity go for up to 3 hours, improving glucose tolerance.

Meaning that people that exercise may have greater glucose levels immediately after training, but have better glucose tolerance across the day.

Both moderate and intense exercise have similar effect on glucose tolerance after a meal.

These body adaptations don’t last forever. If training stops, the body’s response to glucose reverts to normal.

🥊 Summary

Acute exercise has an immediate and intensity-dependent effect on improving glucose tolerance after a meal and insulin sensitivity.