Dr. Sarah Berry: Why eating after 9 quietly grows belly fat

Berry shows that an apple, apple purée, and apple juice have the same ingredients but different structures, leading to different eating speeds, fullness, blood sugar responses, and subsequent calorie intake. Her trials with almonds and oats found that whole almonds vs. finely ground almonds, and large oat flakes vs. milled oats, produced dramatically different absorption and blood sugar curves despite identical labels. Whole, less‑processed structures often slow absorption, increase satiety, and reduce effectively absorbed calories.

Research Berry cites shows that eating 20% more slowly reduces calorie intake by around 15%, and fast eaters consume about 120 extra calories per day vs. slow eaters, even after adjusting for confounders. Clinical trials where people were instructed to slow eating led to more weight loss compared to controls. Chewing more (e.g., ~40 vs. 15 chews per mouthful) alters satiety signals and where food is absorbed in the gut, shifting it lower where more ‘fullness’ receptors are located.

In ZOE data on 1,000 people, 30% snacked after 9 p.m., and late‑night snacking was associated with more abdominal fat, higher inflammation, and worse blood lipids, regardless of snack quality. Berry explains chrononutrition: every cell has a clock, and eating out of sync (late at night) disrupts metabolic processing, hunger, and even how hungry you feel the next morning. Early time‑restricted eating (e.g., finishing food earlier) appears more beneficial than late windows.

In a six‑week RCT, participants replaced 20% of daily energy with either typical UK snack muffins (high in sugar, saturated fat, refined carbs; low in fiber) or almonds. The almond group had significantly improved vascular function, equivalent to an estimated 30% reduction in cardiovascular disease risk. Berry notes 25% of UK/US calories come from snacks, and ~70–75% of those are unhealthy, so simply upgrading snacks to nuts, whole foods, or high‑fiber options is a powerful, practical lever.

Berry calls the online panic about seed oils “nutribollocks,” citing meta‑analyses of RCTs (including ~42 trials) showing seed oil–rich polyunsaturated fats lower LDL cholesterol and cardiovascular risk compared with saturated fats like beef tallow. She clarifies that nuts do not cause weight gain in trials because 20–30% of their calories are not absorbed and they increase satiety and support the microbiome. Fermented dairy (cheese, plain yogurt/kefir) appears neutral or beneficial for cholesterol despite high saturated fat, whereas butter and animal fats like tallow do raise LDL.