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El Catrin, a new Mexican eatery in the Distillery district in Toronto. We don’t know the optimal time to eat the last meal of the day, but it seems to make sense to eat it early and keep it light.Peter Power/The Globe and Mail

The question: I've heard I shouldn't eat dinner after 8 p.m. if I want to lose weight. Does that apply if I stay up late?

The answer: As a dietitian in private practice, I have always advised my weight-loss clients to avoid eating their last meal later in the evening (unless, of course, they work a night shift). Doing so helps them sleep better and feel less bloated the next day.

Eating earlier in the evening also allows you to wake up with an appetite for breakfast, likely the most important meal for optimizing your metabolism and preventing abdominal obesity.

Even so, most experts have argued that eating a 600-calorie dinner at 6 p.m. or 10 p.m. wouldn't make a difference to your weight, providing you're not exceeding your daily calorie allowance. There was little evidence to support the notion that meal-timing influences body weight. Until recently.

Earlier this year, findings from a study published in the journal Obesity strongly suggest that when you eat your calories makes a difference to losing weight. Among 93 overweight women following a 1,400-calorie diet, those who ate a big breakfast (700 calories) and light dinner (200 calories) lost more than twice as much weight as women who ate a 200-calorie breakfast and 700-calorie dinner.

Dieters who ate more in the morning and less in the evening felt less hungry during the day and had lower blood levels of a hunger hormone called ghrelin. (Ghrelin stimulates appetite, increases food intake and promotes fat storage. The hormone also increases after dieting, which may explain, in part, why it can be difficult to maintain a weight loss.)

The researchers speculated that eating a large meal late in the day disrupts the body's internal 24-hour clock and promotes weight gain. Your internal clock, or circadian rhythm, governs metabolism and how the body handles fat and sugar.

This suggests it doesn't matter how late you stay up. Eating late in the evening will throw off your circadian clock whether you go to bed at 10 p.m. or 2 a.m. (Sleep deprivation and shift work can also disrupt our biological clocks and lead to weight gain.)

Other research has suggested that our bodies burn more calories to process breakfast than lunch and dinner.

We don't know the optimal time to eat the last meal of the day, but it seems to make sense to eat it early and keep it light. Stick to protein (e.g. fish, poultry, lean meat, egg whites, beans, tofu) and vegetables. Go easy on starchy foods (e.g. pasta, rice, potatoes, bread). At the very least, you'll improve your digestion and feel better the next morning.

Leslie Beck, a registered dietitian, is based at the Medisys clinic in Toronto. She can be seen every Thursday at noon on CTV News Channel's Direct (

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