Media moguls have sabotaged the idea of eating at night, instilling a fear of weight gain and slow metabolism if you dare let a snack go near your mouth after 7 pm. From published literature, these media moguls saw that people with disordered nighttime eating (wake up and binge eat/drink) and night shift workers would experience weight gain and slowed metabolism when they chronically ate food at night. So, in true fashion, they skewed the data and urged everyone to avoid nighttime eating – and took it as far to say that you should never eat after dinner. However, what they left out was that these populations eat HUGE amounts of Calories (upwards of 1,000) and very carbohydrate- and fat-dense foods (with very minimal protein) – not the typical practice of a normal American.
Furthermore, anecdotally, we know that many athletes, exercisers and bodybuilders consume a snack (~200 Calories) before going to sleep, and that this snack is usually protein-dense. They do this so that they can preserve muscle protein synthesis (which may lead to muscle mass increases) in order to recover overnight. The lack of eating during the ~8-hour window of sleep leads to a catabolic, or breakdown state, which protein can decrease.
The good news is that with more recent and innovative research, researchers are finding that nighttime isn’t as bad after all! Even though, interestingly, there is some merit behind the recommendations to evade nighttime eating – however, with some caveats that are important to mention. When we eat Calories at night versus during the day, metabolism is different. For example, eating a meal during the day will elicit increases in metabolism compared to if you ate the same meal in the evening hours. In addition, in the evening hours, metabolism slows –when you think metabolism, think your body’s capacity to burn Calories – and when this happens we burn Calories at a slower rate. But, why?
1. The stomach slows emptying at night
Food is moved more slowly from our stomachs to our intestines at night compared to the day time. When this happens, nutrient absorption and delivery to important cells (think muscle cells) also slows, which slows metabolism!
2. Cells become increasingly resistant to the storage hormone, insulin at night
Insulin promotes uptake of key nutrients like carbs into the muscle cells. When our muscle cells become resistant to insulin at night, less nutrients are shuttled in, which again slows metabolism.
Eating at night may do more good for you than you think:
1. Aids in muscle recovery overnight
Eating protein before bed versus nothing at all stimulates an increase in protein delivery to muscle which will help recovery. Even better is that when you exercise at night, and you take protein (versus no exercise with protein), protein delivery to muscle is increased. So, jiu-jitsu at night primes the muscle!
2. Increases muscle mass and strength gains, and doesn’t affect fat
Combined with a long term resistance training program, consuming protein at night will help you increase muscle mass and strength greater than consuming nothing. The good thing is that you won’t gain fat mass!
3. May increase metabolism the next morning
In active individuals, metabolism (Calories that you burn sitting) the next day increases when you eat protein (whey or casein) and carbohydrate compared to eating nothing before bed.
4. Does not change fat release from fat cells, burning fat for energy at night
Whether you eat something or nothing, your body releases stored fat from fat cells and relies on fat as a fuel at the same rate. Casein is the best choice in active populations!
5. Decreases hunger and increases satiety the next morning
6. Does not change hormones acutely or chronically
What should you eat at night? Stick with protein-rich choices. To date, most metabolic nighttime eating research includes liquid beverages, like a protein shake. One study from Florida State University is assessing the effects of nighttime consumption of a whole food (cottage cheese) versus a protein shake on next-morning metabolism. Results are forthcoming!
If you are going with protein, choose casein. Casein is a slow-releasing, which means that after absorption, the proteins are released as a steady rate over a long period of time. Therefore, metabolism and muscle protein synthesis are optimized over the long period of sleep. Casein protein as a shake can be pretty thick, and thus sometimes feels and tastes like a milkshake, which is definitely a treat at night! You may also see similar effects with whole foods that are high in casein like milk-based products (i.e. cottage cheese), but these effects have not been published, so the jury is still out!
Overall, nighttime eating should not be dreaded! However, you can refine this dietary practice in order to optimize metabolism by consuming ~200 Calorie protein snacks, such as casein protein or cottage cheese.