Small Frequent Meals vs Intermittent Fasting
Today’s “Ask the Nutrition Consultant” question comes from Carrie!
Q: In the past we were always told to eat 5 to 6 small meals per day. Now I’m constantly hearing about intermittent fasting. Eating often throughout the day versus eating within a small window of time seem like completely different ends of the spectrum. What are your thoughts on this? Is one or the other better for a woman in her 40’s who would like to lose some weight?
A: Thanks for your question Carrie! You are right, they are two very different eating patterns. Neither eating pattern is required or necessary to maintain an ideal body weight or body composition and I do not regularly use them with clients – unless they have a specific medical condition that may warrant it.
Small Frequent Meals
This is going to come as a shock to many, but frequent small meals do not increase our metabolic rate, control blood sugar levels, or reduce cravings and hunger as was once thought.
First let’s look at metabolic rate, which is the amount of energy expended over a specific period of time. While we do burn some calories in order to digest food, known as the thermic effect of food, it is a very small amount of our total energy expenditure (~10%) and it is based on the total amount of food consumed, not how many meals we have. For example, eating 3 meals of 600 calories will cause the same thermic effect as eating 6 meals of 300 calorie meals. There is no difference. Eating more often will not increase your “calorie burn” (Cameron, Cyr, & Doucet, 2010).
But what about balancing blood sugar levels, hunger and cravings? Eating large meals is thought to lead to more highs and lows in our blood sugar levels, while smaller more frequent meals were thought to stabilize blood sugar levels. Studies do not support this. In fact, eating small meals every 2 to 3 hours causes blood glucose levels to stay elevated throughout the day (Holmstrup, Owens, Fairchild, & Kanaley, 2010).
We do not want our blood sugar levels to stay elevated. Consistently high blood glucose levels are damaging to the body and can damage blood vessels and increase the risk of heart disease and stroke, kidney disease, vision problems, and nerve problems. Constantly eating and having consistently high blood sugar levels is taxing to our pancreas which produces insulin. Insulin is the hormone that helps shuttle glucose out of the blood stream and into our cells. Long term, this can lead to health concerns such as insulin resistance and type II diabetes mellitus.
Small frequent meals can also increase hunger and cravings. Our stomach and intestines are filled with mechanoreceptors or stretch receptors. When these receptors detect the stretching of the stomach and intestinal wall they send nerve signals to the brain that “we’re full, stop eating!” Small meals may not activate these stretch receptors and can leave us constantly feeling hungry.
One of the biggest concerns I have with eating small frequent meals is that the body never gets a chance to burn what we have stored. If we have a constant supply of food coming in there is no reason for our body to burn stored body fat and glycogen. Eating small frequent meals can actually hinder our weight loss goals and prevent us from accessing and burning body fat.
Intermittent fasting or time-restricted eating is when you only eat during a specific window of time each day. During the fasting hours you are only allowed to drink water, coffee and tea. One of the most popular intermittent fasting diets is the 16:8 diet where you eat during an eight hour window and fast for the other 16 hours.
There’s potential to lose weight with intermittent fasting, as it can help lower insulin levels and promote fat burning, but research shows that it’s not any more effective than a traditional calorie-restricted diet (Harris et al., 2018). The composition and quality of the foods consumed during feeding hours matter too. Unfortunately this is often overlooked and most think they can eat whatever they want and still lose weight. Even in a small feeding window a person could over consume and cause weight gain.
One benefit of fasting is a cellular repair process called autophagy. Autophagy means “self eating” and it is the body’s way of repurposing damaged cell components for energy and to create new, healthier cells. Autophagy and the clean-up of old and damaged cells and debris may provide protection against aging, cancer, and Alzheimer’s disease. While it may not bring on full autophagy, even doing a 12 hour overnight fast can be beneficial for cellular repair and healing. I recommend everyone give their digestive tract a 12 hour “break” every day so that energy and resources can go towards healing instead of digesting food. For example, if your last meal of the day is at 7pm, do not eat your first meal of the following day until 7am, 12 hours later.
A concern with intermittent fasting is its effects on reproductive hormone levels in women and men. Very few studies have been conducted on this topic, and those that have been done show a decrease in androgens (like testosterone) in both sexes. These hormonal changes have various health implications. They could be beneficial for helping a woman dealing with hyperandrogenism and PCOS, but for men it could negatively affect metabolic health, fertility, and libido (Cienfuegos et al., 2022).
Summing it Up
The best way to maintain an ideal body weight, body composition, and health is to eat a balanced diet of whole, real foods. Eating at least 20 grams of protein, healthy fats, and unrefined carbohydrates at every meal will help to stabilize blood sugar levels, energy levels, and hunger cues.
Ideally, we should not need to eat every 2-3 hours or snack between meals. We should be able to go ~5 hours between meals. If you find you are constantly hungry or need to eat every 2-3 hours that tells me that you either didn’t eat enough food, and/or your meal wasn’t balanced with protein/fats/carbs. Proteins, fats, and fiber rich foods take longer to digest, help prevent blood sugar spikes and increase satiety.
My general recommendation is to eat 3 well balanced meals per day and the occasional snack if needed. Sometimes we have a long stretch between meals and in those cases having a healthy snack can help tide you over and stabilize blood sugar and energy levels. Some mid-meal snacks that I recommend include: organic grass-fed beef jerky, organic grass-fed cheese and some fruit, veggies and hummus, hardboiled eggs.
If you are confused about all the conflicting nutrition info out there and and want dietary and lifestyle recommendations specific to you and your health call or e-mail me to set up a complimentary Nourish to Flourish Strategy Session to chat.
Amanda Watson, BCHN®
Alirezaei, M., Kemball, C. C., Flynn, C. T., Wood, M. R., Whitton, J. L., & Kiosses, W. B. (2010). Short-term fasting induces profound neuronal autophagy. Autophagy, 6(6), 702–710. https://doi.org/10.4161/auto.6.6.12376
Cameron, J. D., Cyr, M. J., & Doucet, E. (2010). Increased meal frequency does not promote greater weight loss in subjects who were prescribed an 8-week equi-energetic energy-restricted diet. The British journal of nutrition, 103(8), 1098–1101. https://doi.org/10.1017/S0007114509992984
Cienfuegos, S., Corapi, S., Gabel, K., Ezpeleta, M., Kalam, F., Lin, S., Pavlou, V., & Varady, K. A. (2022). Effect of Intermittent Fasting on Reproductive Hormone Levels in Females and Males: A Review of Human Trials. Nutrients, 14(11), 2343. https://doi.org/10.3390/nu14112343
Glazier, E., Ko, E. (2018, March 13). Ask the doctors – are 6 small meals a day better than 3 big ones? UCLA Health System. Retrieved March 30, 2023 from https://www.uclahealth.org/news/ask-the-doctors-debating-the-benefits-of-eating-six-small-meals-a-day.
Harris, L. , Hamilton, S. , Azevedo, L. , Olajide, J. , De Brún, C. , Waller, G. , Whittaker, V. , Sharp, T. , Lean, M. , Hankey, C. & Ells, L. (2018). Intermittent fasting interventions for treatment of overweight and obesity in adults: a systematic review and meta-analysis. JBI Database of Systematic Reviews and Implementation Reports, 16 (2), 507-547. doi: 10.11124/JBISRIR-2016-003248.
Holmstrup, M., Owens, C., Fairchild, T., Kanaley, J. (2010). Effect of meal frequency on glucose and insulin excursions over the course of a day. e-SPEN, the European e-Journal of Clinical Nutrition and Metabolism, Volume 5, Issue 6, 2010, Pages e277-e280, ISSN 1751-4991.