Intermittent fasting (IF) is a dieting approach based on timing. Many choose the popular 16:8 method, which involves a 16-hour fast followed by an 8-hour eating window. However, knowing when to eat can be confusing for those who are just starting their IF journey. You’re probably wondering whether you should skip breakfast or dinner and what the best option is for your schedule and lifestyle. Here are some answers to those questions.

Choose to skip breakfast if:

• Your social life involves dinner with family or dining out. (After all, dinner tends to be the most social meal of the day.)
• You work late hours and wake up late in the morning.
• It’s easier to skip breakfast because you aren’t hungry in the morning. Certain hormones (i.e. growth hormones, melatonin, prolactin, cortisol, and aldosterone) go up before waking up. These hormones help the body convert stored calories into energy. Because of this process, you may not feel hungry in the morning. 
• You’re a late riser and enjoy sleeping during the morning hours.
• You always rush out the door in the morning. Skipping breakfast saves time, and it’s better to not eat at all than to eat in a hurry. 

Things to consider:

• Scientists continue to discuss whether early or later eating times are ideal.  Many clinical studies are based on a required early feeding window (i.e. 8 am to 2 pm), though, in some cases, participants chose their preferred eating window. There are also many studies evaluating IF during Ramadan, where participants did not eat from sunrise to sunset, skipping breakfast and fasting 10-18 hours. We will likely have more data in the future, as researchers plan to evaluate IF patterns by measuring the chronotype (e.g., whether you are a morning vs. evening type of person) and preferred sleep times. We will continue to keep you informed of the latest studies.
• Some studies have found that the timing of food consumption may change the metabolic response. Compared with eating earlier in the day, eating late at night has been linked to excess weight and difficulty losing weight. Therefore, if you decide to skip breakfast, always avoid eating your last meal just before bed. Because it takes several hours to digest proteins and fats, it could disturb your sleep.

Choose to skip dinner if:

• You don’t often eat out.
• You work late hours and don’t have time to eat dinner. 
• You like to go to bed early.
• You’re an early riser and tend to get hungry early in the morning. 

Things to consider:

• Eating earlier may help you consume fewer calories since dinners are typically larger than breakfasts. Additionally, since we are wired to eat and be active during the day and sleep at night, eating earlier will optimize the benefits of IF, according to Harvard researchers. Choose to eat between 7 am and 3 pm or, if you need a later schedule, between 10 am and 6 pm. 

• However, keep in mind that skipping dinner may not be suitable for your social obligations and overall lifestyle. For example, if you eat dinner with your family each night, an earlier intermittent fasting schedule may not make sense. 

The Bottom Line

Skipping breakfast may be easier, but skipping dinner may be more effective. Ultimately, the best way to determine the best IF pattern is to listen to your body. Choose an option to try and see how you feel. As you start your IF journey, it’s important to remember that it takes a few weeks for the body to adjust to IF. You may feel hungry, irritable, or tired at the beginning. However, if you make it through the first couple of weeks, you’ll adjust to the routine and be able to make thoughtful changes that will help you stick to it long-term.