The Nutritional Scientist: Do Not Eat After 9pm! Link Between Chewing & Belly Fat!

PostedJanuary 27, 2025

Here are the top 10 key takeaways from Dr. Sarah Berry's conversation on "The Diary of A CEO" podcast that could transform how you think about nutrition, eating habits, and their impact on your health.

1. Food matrix matters more than nutrients alone

The food matrix refers to the structure of food, which significantly impacts how our bodies process nutrients. Two foods with identical nutritional labels can have entirely different health effects because of their structure and processing.

For example, whole apples, apple puree, and apple juice all come from the same source but have different structures that affect how our bodies respond to them. Studies show that apple puree is consumed 3-4 times faster than whole apples, leading to less fullness and potential blood sugar dips later. This demonstrates why focusing solely on nutrients without considering the food's structure gives an incomplete picture.

Similarly, research with nuts shows that when consumed whole, about 20-30% of the calories pass through undigested because the rigid cell walls encapsulate the fat. When those same nuts are finely ground, nearly 100% of calories are absorbed. This illustrates why whole foods often have different metabolic impacts than their processed counterparts, even when the nutrient content appears identical on labels.

2. Eating speed significantly affects calorie consumption

The speed at which we eat our food has substantial impacts on how much we consume. Research shows that changing eating speed by about 20% can reduce calorie intake by approximately 15%.

When we eat quickly, we often consume more calories because fullness signals take time to reach our brain. It typically takes 10-20 minutes for satiety hormones to be released and signal to our brain that we're full. Fast eaters consume approximately 120 more calories per day than slow eaters, according to studies. This difference accumulates over time and can significantly impact weight.

Studies have shown that chewing food more thoroughly also affects satiety. Chewing food 40 times versus 15 times results in greater feelings of fullness. This simple habit change can have meaningful effects on overall consumption. Clinical trials demonstrate that people who intentionally slow their eating rate lose more weight than those who maintain their normal eating speed.

3. Late-night snacking negatively impacts health regardless of snack quality

Snacking after 9 PM is associated with unfavorable health outcomes, even when consuming nutritious foods. About 30% of people snack after 9 PM, and research shows this correlates with higher levels of abdominal fat, inflammation, and worse blood lipid profiles.

This happens because every cell in our body has its own internal clock that functions optimally when we eat in sync with our circadian rhythms. When we eat late at night, we disrupt these cellular clocks, causing our bodies to process food differently and potentially store more energy as fat around the abdomen. Our metabolism needs rest overnight, just like our mind does.

Research demonstrates that people who consume most of their calories earlier in the day wake up feeling less hungry than those who eat later. This contradicts what many might expect but shows how timing impacts our hormonal responses. For better health outcomes, early time-restricted eating (eating within a 10-12 hour window earlier in the day) appears more beneficial than eating later into the evening.

4. Sleep quality profoundly influences food choices and metabolism

Poor sleep quality or insufficient sleep duration directly impacts hunger levels, food choices, and how the body processes nutrients. Sleep deprivation leads to increased hunger upon waking and greater likelihood of choosing less healthy foods.

A study at King's College London showed that when short sleepers practiced good sleep hygiene, they naturally reduced their intake of free sugars by about 10 grams without any dietary instruction. This demonstrates how improving sleep can automatically lead to better dietary choices. Sleep affects hunger and fullness hormones, which then influence both appetite and food preferences.

Research shows that the blood glucose response to identical meals is significantly higher after a poor night's sleep compared to after a good night's sleep. This creates a harmful cycle: poor sleep leads to increased hunger, less healthy food choices, and worse metabolic responses to those foods. These factors combine to create what Dr. Berry calls "a perfect storm" that begins with inadequate sleep.

Despite widespread claims on social media that seed oils (like canola and sunflower oil) are toxic and linked to diseases like Alzheimer's and cancer, scientific evidence does not support these assertions. In fact, research indicates that seed oils can be beneficial for health.

The narrative against seed oils often relies on correlation data showing increased consumption alongside rising disease rates without accounting for numerous other lifestyle changes during the same period. Other arguments use theoretical biochemical pathways that don't actually play out in human bodies, which have sophisticated mechanisms to control inflammation and oxidative stress.

Meta-analyses of approximately 42 randomized controlled trials comparing seed oils to other fats consistently show reduced cardiovascular disease risk with seed oils. This is largely due to their cholesterol-lowering effects. Studies directly comparing seed oils to beef tallow (which contains saturated fat) have shown that seed oils produce better health outcomes, including reduced cholesterol and inflammation markers.

6. Dairy products have varied health effects based on processing

Not all dairy products have the same health impacts, and grouping them together oversimplifies their diverse effects. The health implications depend largely on whether the dairy is liquid, solid, fermented, or non-fermented.

Fermented dairy products like cheese and yogurt undergo processes that change their food matrix, altering how our bodies respond to them. Despite having high saturated fat content, studies show that consuming moderate amounts of cheese and yogurt does not increase cholesterol levels. The fermentation process appears to modify the food structure in ways that mitigate the negative effects typically associated with saturated fat.

In contrast, butter does increase cholesterol levels when consumed in significant quantities. Randomized controlled trials comparing cheese and butter with nearly identical fat compositions show that butter raises cholesterol while cheese does not. This highlights why understanding food processing is crucial for making informed dietary choices rather than simply avoiding entire food groups.

7. The menopause transition significantly alters metabolism and food responses

During perimenopause and menopause, hormonal changes profoundly impact how women respond to food. The fluctuation and eventual decline of estrogen creates metabolic changes that affect everything from hunger signals to how the body processes nutrients.

Research shows that postmenopausal women have five times greater risk of heart attacks and abdominal obesity compared to premenopausal women. Studies demonstrate that cholesterol levels, particularly LDL ("bad") cholesterol, increase by approximately 25% during this transition. Postmenopausal women also experience larger spikes in blood glucose and fat after meals compared to premenopausal women.

The symptoms of menopause are widespread and often misunderstood. While hot flashes are commonly associated with menopause, they affect only about 40% of women. More prevalent symptoms include brain fog, anxiety, and memory loss, which impact approximately 85% of perimenopausal women. These symptoms significantly affect quality of life, with about 10% of women leaving the workforce due to the burden of menopausal symptoms.

8. Diet quality can reduce menopausal symptoms by approximately 35%

Research indicates that dietary improvements can substantially reduce menopausal symptoms. Studies show that transitioning to a healthier diet pattern can reduce symptom burden by about 35%, which represents a significant improvement for women experiencing menopausal discomfort.

While hormone replacement therapy (HRT) can be effective for many women, diet offers an additional or alternative approach. Research specifically examining Mediterranean-style diets in randomized controlled trials has shown similar reductions in symptom severity. These diets emphasize increased plant diversity, higher fiber intake, and healthy fats, which appear to help regulate hormonal fluctuations.

Soy isoflavones stand out as one of the few supplements with scientific evidence supporting their effectiveness for menopausal symptom relief. These compounds have a structure similar to estrogen and can bind to estrogen receptors in the body. In countries where dietary intake of soy isoflavones is high (approximately 70mg daily in East Asian countries versus 1mg daily in Western countries), the prevalence of menopausal symptoms is notably lower.

9. Time-restricted eating provides benefits even with modest implementation

Research shows that simply limiting eating to a 10-12 hour window can provide significant health benefits without the extreme restrictions often associated with intermittent fasting. This approach makes healthy eating patterns more sustainable for everyday life.

Studies indicate that even when people aren't explicitly told to reduce calories, limiting their eating window naturally reduces energy intake by about 300 calories per day on average. The "Big IF" study with 150,000 participants found that people practicing a 10-hour eating window (for example, eating between 10 AM and 8 PM) reported better energy, improved mood, and weight loss within just two weeks of implementation.

While smaller eating windows produce greater weight reduction, there are benefits independent of calorie reduction. Controlled studies show improvements in blood lipids and inflammation markers even when calorie intake remains the same but is consumed within a shorter timeframe. This suggests that aligning eating patterns with our body's natural rhythms provides metabolic advantages beyond simple calorie control.

10. Consistency in eating patterns matters for metabolic health

Maintaining consistent eating and sleeping patterns appears to be important for metabolic health. Research on "social jet lag" (having inconsistent sleep schedules between weekdays and weekends) shows negative impacts on dietary choices, inflammation levels, and gut microbiome composition.

People who experience social jet lag of more than 1.5 hours difference between work days and weekend days make poorer dietary choices and show higher inflammation markers. This inconsistency disrupts the body's internal clocks, similar to traditional jet lag when traveling between time zones. The disruption appears to cascade through multiple systems that regulate metabolism and hunger.

For those who are typically snackers, maintaining that pattern with healthy snacks is better than suddenly changing eating frequency. Similarly, those who normally eat three distinct meals should maintain that pattern rather than adding snacks. This consistency allows the body to establish reliable metabolic rhythms and hormone release patterns, contributing to better overall health outcomes and more predictable energy levels throughout the day.