Is WHEN you eat, as important as WHAT you eat?
Does when you eat really make a difference to your health? Can eating at certain times improve weight loss? But more specifically is time-restricted eating (TRE) as effective or better than eating regularly throughout the day?
Research suggests that the time you eat links to your circadian rhythm or sleep cycle which also orchestrates 24-hour rhythms in metabolism, physiology, and behaviour. Furthermore, a large proportion of plasma lipids, hormones like cortisol, and growth hormones all work within a 24-hour period.
These rhythms are produced through the coordination of transcriptional and translational feedback loops involving clock genes that affect insulin sensitivity and the thermic effect of food, which both peak in the morning (Poggiogalle et al, 2018). As a result of this morning peak, metabolic rhythms down regulate in the evening and may impair your cardiometabolic endpoint, suggesting the morning is the optimal time for food intake.
There is so much research on this subject so let me explain in this blog why eating regularly has its place but also why intermittent fasting and more specifically time-restricted eating, is potentially more beneficial for your body.
Eating Regularly
Eating regularly is a brilliant way to stabilise the body and deliver the fuel and nutrients it requires throughout the day. It is particularly important if you have stress on the body and your adrenals are under pressure, or when nutrient status has been depleted significantly by on-going stressors.
Eating regularly enables the body to gain a natural rhythm, it helps to regulate blood sugars so they do not drop excessively leading to the overindulging of unhealthy foods. Your bodies are programmed to sense a lack of food as starvation. When you skip meals, your metabolism slows down making it harder to lose weight.
Eating regularly fuels your body, if your body is running on empty, it can’t operate well - affecting your mood and daily performance. The hungrier you are, the harder it is to make good decisions. Think about going to the shops when you are ravenous –are you likely to grab something healthy? Nearly anything is more tempting as your body craves sugar and salt -you are likely to reach for that crisp packet and chocolate bar.
When you eat regularly your body has the energy it needs. A study by Yoon et al, 2021, suggests that people who consume breakfast and regular meal times have healthy lifestyle habits and adequate nutrient intake, which affect metabolic health, thereby helping prevent obesity and related metabolic disorders. As creatures of habit it is likely your routine impacts your health positively. By making regular meals a priority, you help your body establish a healthier lifestyle.
Intermittent Fasting or Time Restricted Eating (TRE)
Time-restricted eating is a type of intermittent fasting focusing on when to eat rather than what to eat but they evoke slightly different associations. Intermittent fasting implies calorie restriction, with periodic 24-hour fasts and intermittent energy restrictions such as the 5:2 diet where you fast for 5 hours and eat for 2 hours. While TRE permits a person to eat as much as they want during a specific eating window. TRE aligns the eating and fasting cycles to the body's innate 24-hour circadian system and tends to be easier to adhere to especially if the restriction is overnight. However, what you eat in this window can also play a role in health outcomes.
Both TRE and intermittent fasting have a similar effect on body function. Benefits are greater than just your waistline, fasting stabilises your blood sugar levels, reducing inflammation and keeps your heart healthy. In a study published by the NCBI, intermittent fasting has been shown to be increasingly effective within animal models to improve cardiometabolic health, reduce cancer, slow down tumour growth and regenerate organs. In humans, data on intermittent fasting suggests that it decreases body weight, insulin levels, blood pressure, inflammation, and appetite, and therefore improves insulin sensitivity and lipid profiles.
Six positive effects of Intermittent Fasting and TRE
1. Improves weight
TRE speeds up fat burning and is preferable to dieting because it does not require you to meticulously measure your food or track calories. It forces the body to use up fat stores as fuel. When you eat, your body uses glucose (sugar) as its primary source of energy and stores whatever is left over as glycogen in your muscles and liver. When you do not give your body a steady stream of glucose, it begins breaking down the glycogen to use as fuel. After the glycogen has been depleted, your body seeks out alternative sources of energy, such as fat cells, which it then breaks down to help power your body. This is similar to the keto diet where you deprive your body of carbohydrates and force it to use up stored fat for energy.
A 2015 review by Tinsley et al, looked at the effects of alternate-day fasting on body composition and found that, it decreased body weight, cut body fat and reduced weight. A study of TRE consistently for 8 weeks by Moro et al, 2016, showed significantly reduced fat mass and the retention of both muscle mass and strength.
2. Improves Blood Sugar
Studies have found that intermittent fasting benefits your blood sugar levels by keeping them well-regulated, preventing spikes and crashes. A study by Arnason et al, 2017 showed that short-term daily fasting improved key outcomes in type 2 diabetics including improved body weight, fasting glucose and postprandial variability.
Glucose homeostasis can also be managed by fasting. Gnanou et al, 2015, found that fasting decreased blood sugar by 12%, lowering insulin levels by nearly 53%. Preventing a build-up of insulin allows it to work more efficiently and keeps your body sensitive to its effects.
3. Keeps Your Heart Healthy
Studies show that intermittent fasting improves your heart health by lowering certain heart disease risk factors. It increases good HDL cholesterol and decreases both bad LDL cholesterol and triglyceride levels. (Shehad et al, 2021). Adiponectin, a protein involved in lipid metabolism, energy regulation, immune response, inflammation and insulin sensitivity may also be increased by fasting and be protective against heart disease and heart attacks (Khoramipour et al 2021).
4. Reduces Inflammation
Inflammation is a normal immune response to injury. Chronic systemic and long term inflammation however, can lead to heart disease, diabetes, obesity and cancer (Amin, et al 2019).
A study in 2012 by Nutrition Research followed 50 individuals who had decreased levels of inflammatory markers during Ramadan fasting (Kacimi et al, 2021). Another study by Marinac et al, 2015, found that a longer duration of night time fasting was associated with a decrease in markers of inflammation and other studies showed a reduction in oxidative stress. All showing that TRE may reduce inflammation and fight off chronic disease.
5. Protects Your Brain
Based on a few research findings, promoting healthy brain ageing and preventing neurodegenerative diseases by intermittent fasting, seems to be a promising approach (Frances N, 2020). The anti-inflammatory and mild ketosis effects of intermittent fasting may also help slow the progression of neurodegenerative disorders like Alzheimer’s disease (Newport M, 2021).
6. Decreases Hunger
Your satiety hormone leptin produced by fat cells, helps signal when it is time to stop eating. Leptin levels drop when you are hungry and increase when you are feeling full. Those who are overweight or obese tend to have higher amounts of leptin circulating in the body and too much leptin floating around can cause leptin resistance, which makes it harder for it to effectively turn off hunger signals.
During fasting, Leptin levels have been found to be lower at night (Alzoghaibi et al, 2014). Lower levels of leptin could translate to less leptin resistance, less hunger and potentially more weight loss.
When to avoid Intermittent Fasting
· If you are stressed, as you may not digest effectively and therefore not absorb enough nutrients to function optimally.
· If you suffer from low blood sugar - dangerous drops in blood sugar may cause shakiness, heart palpitations and fatigue.
· History of eating disorders as it may encourage unhealthy behaviours and trigger symptoms
· Anyone who is sick as it can deprive your body of nutrients for healing.
· Those who are pregnant should focus on a nutritious diet rich in vitamins and minerals with no restrictions to healthy eating.
· Gallstone issues may increase risk of gallbladder problems.
· Fasting may alter thyroid hormones causing more risk.
· Anyone training hard. Avoid exercising on long fasting days. Do not push yourself too hard an d remember to drink plenty of water.
In summary, when you eat is definitely as important as what you eat. Eating regular meals is a key step to healthy lifestyle habits and adequate nutrient intake, which positively affects metabolic health. It is also safe and easy for the majority of people to stick to. Intermittent fasting has positive effects on weight loss and fat burning, regulating blood sugar, protecting the brain, heart reducing inflammation but it may not be a good fit for everyone and depending on the type of fasting may be difficult to adhere to.
In clinic as a registered Nutritional Therapist, I aim to discover the body system that can be supported by healthy food and lifestyle choices for the greatest and most effective change. I then work out established patterns that could be holding recovery back and encourage changes to both habits and patterns.
I tend to begin by establishing eating regularly (7am, 10am, 1pm, 4pm, 7pm) with 12hr TRE overnight (7pm-7am) to rest digestion and body functions, enabling good clearance of toxins and healing overnight. This not only stabilises the body but ensure enough fuel and nutrients are consumed to support adrenal function as well as sleep. From there, depending on the individual and if the body is digesting well and balance is established, I may increase the rest period overnight.
If you are interested in improving your health and working with me or you are interested in finding out more, then please get in touch for a quick no obligation chat here
https://www.bespokenutritionaltherapy.co.uk/contact
References
Alzoghaibi, M.A., Pandi-Perumal, S.R., Sharif, M.M. and BaHammam, A.S., 2014. Diurnal intermittent fasting during Ramadan: the effects on leptin and ghrelin levels. PloS one, 9(3), p.e92214.
Amin, M.N., Hussain, M.S., Sarwar, M.S., Moghal, M.M.R., Das, A., Hossain, M.Z., Chowdhury, J.A., Millat, M.S. and Islam, M.S., 2019. How the association between obesity and inflammation may lead to insulin resistance and cancer. Diabetes & Metabolic Syndrome: Clinical Research & Reviews, 13(2), pp.1213-1224.
Arnason, T.G., Bowen, M.W. and Mansell, K.D., 2017. Effects of intermittent fasting on health markers in those with type 2 diabetes: A pilot study. World journal of diabetes, 8(4), p.154.
Francis, N., 2020. Intermittent fasting and brain health: Efficacy and potential mechanisms of action. OBM Geriatrics, 4(2), pp.1-1.
Gnanou, J.V., Caszo, B.A., Khalil, K.M., Abdullah, S.L., Knight, V.F. and Bidin, M.Z., 2015. Effects of Ramadan fasting on glucose homeostasis and adiponectin levels in healthy adult males. Journal of Diabetes & Metabolic Disorders, 14(1), pp.1-6.
Hunter, P., 2012. The inflammation theory of disease: The growing realization that chronic inflammation is crucial in many diseases opens new avenues for treatment. EMBO reports, 13(11), pp.968-970.
Kacimi, S., Ref'at, A., Fararjeh, M.A., Bustanji, Y.K., Mohammad, M.K. and Salem, M.L., 2012. Intermittent fasting during Ramadan attenuates proinflammatory cytokines and immune cells in healthy subjects. Nutrition research, 32(12), pp.947-955.
Khoramipour, K., Chamari, K., Hekmatikar, A.A., Ziyaiyan, A., Taherkhani, S., Elguindy, N.M. and Bragazzi, N.L., 2021. Adiponectin: Structure, physiological functions, role in diseases, and effects of nutrition. Nutrients, 13(4), p.1180.
Newport, M., 2021. Review of Strategies to Overcome Brain Insulin Resistance Through Mild Nutritional Ketosis for Alzheimer's and Mild Cognitive Impairment. Current Developments in Nutrition, 5(Supplement_2), pp.912-912.
Marinac, C.R., Sears, D.D., Natarajan, L., Gallo, L.C., Breen, C.I. and Patterson, R.E., 2015. Frequency and circadian timing of eating may influence biomarkers of inflammation and insulin resistance associated with breast cancer risk. PloS one, 10(8), p.e0136240.
Moro, T., Tinsley, G., Bianco, A., Marcolin, G., Pacelli, Q.F., Battaglia, G., Palma, A., Gentil, P., Neri, M. and Paoli, A., 2016. Effects of eight weeks of time-restricted feeding (16/8) on basal metabolism, maximal strength, body composition, inflammation, and cardiovascular risk factors in resistance-trained males. Journal of translational medicine, 14(1), pp.1-10.
Poggiogalle, E., Jamshed, H. and Peterson, C.M., 2018. Circadian regulation of glucose, lipid, and energy metabolism in humans. Metabolism, 84, pp.11-27.
Shehab, A., Abdulle, A., El Issa, A., Al Suwaidi, J. and Nagelkerke, N., 2012. Favorable changes in lipid profile: the effects of fasting after Ramadan. PloS one, 7(10), p.e47615.
Tinsley, G.M. and La Bounty, P.M., 2015. Effects of intermittent fasting on body composition and clinical health markers in humans. Nutrition reviews, 73(10), pp.661-674.
Yoon, S.R., Choi, M. and Kim, O.Y., 2021. Effect of Breakfast Consumption and Meal Time Regularity on Nutrient Intake and Cardiometabolic Health in Korean Adults. Journal of Lipid and Atherosclerosis, 10(2), p.240.