How can you lose weight healthily and keep it off? Doctors Felix Kreier and Maarten Biezeveld explain that it begins with calming the hypothalamus—the "hamster" in your brain that constantly checks for available food.
You've likely experienced it: shedding pounds quickly for a special event by following a crash diet. The results look great at first—until the weight returns, often with extras. This yo-yo effect happens because your brain's "hamster" gets stressed, according to doctors Felix Kreier and Maarten Biezeveld. In their book The Hamster in Your Brain, they reveal what occurs in your brain during weight loss and share strategies for doing it right.
What do they mean by the 'hamster' in your brain? Kreier: "The hypothalamus, a small ancient brain region, has one simple job: prevent energy shortages that could lead to death. It scans your surroundings for food, unaware of modern supermarkets, so it urges building extra fat reserves—like a hamster. Luckily, your prefrontal cortex, the brain's 'decision maker,' can rein it in. This rational area handles planning and logic, where weight loss intentions form. But it struggles with multitasking. While focused on dieting, it works well. Distracted by stress, fatigue, or work, the hamster takes over, demanding those lost kilos back—plus more."
Is this why crash diets don't work? Kreier: "Precisely. Rapid weight loss signals famine to the hamster, triggering intense hunger and energy conservation: lower body temperature, slower heart rate, and exhaustion. Paradoxically, it demands even fewer calories to continue losing." Biezeveld: "Crash diets yield no lasting results. They focus on restrictions without building habits. Sustainable loss requires gradual changes—small steps forming automatic healthy choices without riling the hamster."
What angers the hamster? Kreier: "Fast weight loss. A healthy hypothalamus reacts swiftly to depleting reserves. It fights back—you can't change it, but understanding it helps. Gradual reduction provokes a milder response than drastic cuts, avoiding retaliation."
The Hamster Brain method isn't a diet. What is it? Kreier: "A philosophy of healthy living, explaining brain dynamics in weight loss. Three regions interact: hypothalamus, prefrontal cortex, and limbic system—the 'lobbyist' rewarding restraint or indulgence alike." Biezeveld: "Key elements: focus to curb storage urges, new routines, and gradual loss. A slight calorie deficit keeps the hamster calm, reducing hunger for longer progress." Kreier: "We don't dictate meals but teach brain influence. The loudest brain part wins, so outsmart them strategically."
How? Kreier: "Cut calories yet feel full by maximizing sensory input. Fast food lacks texture; home-cooked meals engage sight, smell, and taste, reassuring the hamster. Smaller plates create fullness illusions. No single trick suffices—discover what suits you and build habits. It's challenging, but effective."
How much is healthy weekly loss? Biezeveld: "200 grams—modest but totals 10 kilos yearly. Like slowly melting an ice cube: progress builds invisibly until the breakthrough." Kreier: "Modest deficits spark changes, like better fat distribution—reducing belly fat, a key health risk—even without scale drops." Biezeveld: "Any non-crash approach fits: Pioppi, Mediterranean, or keto. Experiment to find yours. Focus on wholesome eating; our book covers brain processes."
Evaluation matters for maintenance. Daily weighing? Biezeveld: "Track intake to spot patterns and alternatives. Check calories—nuts are healthy in moderation (15g raw, ~8 almonds), not handfuls of salted cashews (750 calories). Weigh thrice weekly at consistent times to avoid rapid loss. Monitor weight, calories, or waist."
Why hard to sustain? Kreier: "Focus fades amid fatigue or busyness; hamster never rests. Plan ahead: enlist friends or move during cravings." Biezeveld: "Sticker a hamster drawing near temptations like the fridge to activate your decision maker."
Proof? Kreier: "My 18-year research at Netherlands Brain Institute, plus recent studies, confirms rule-based diets fail without routines. We simplified for my OLVG overweight kids clinic. Two pilots with 270 participants succeeded impressively."
For taming your hamster? Biezeveld: "Take time—rushing invites rebound." Kreier: "Embrace your brain's debates. Forgive hamster wins; it's part of you."
Text: Kim van der Meulen, Images: Getty Images
