It has been discovered that obesity can increase the risk of a severe Covid-19 infection, therefore you are more likely to have significant complications from Covid-19 if you contract it. It is hence, an opportune time to consider healthy weight loss if you are overweight or obese.
However, many people find weight loss incredibly difficult and, as everyone reacts differently to different eating plans due to physiology, genetics, culture and emotions to name a few, there is no perfect one-size-fits-all way to healthy weight loss. This blog aims to discuss the research behind different methods to try and break the facts away from the fads. It is important to remember that “diets” do not tend to work as they tend not to create long term dietary and lifestyle changes which are necessary to achieve long term sustainable weight loss.
What’s the deal with calories?
Calorie counting is what many people focus on and there are inherent problems with a calorie focused approach. Someone trying to lose weight might have a low calorie breakfast cereal, then at lunch-time they choose a low calorie ‘Meal deal’ that includes a sandwich plus an apple; and perhaps for supper some pasta and low fat sauce; and maybe some low calorie treats (like biscuits or a snack bar). This kind of diet is likely to provide what is considered an appropriate range of calories for weight loss, between 1000 to 1500 calories per day. But eating these foods will have a disastrous impact on blood sugar for many people, resulting in high levels of insulin, and when insulin is high the body goes into fat storage mode! So, you will have come across people who say they are counting calories and can’t lose weight!
The focus on calories should not be the whole story – whilst it is true that if you eat more calories than you need you will gain weight, it is not necessarily true that reducing calories will lead to weight loss. The idea that weight management is about balancing a ‘calorie’ equation – calories in versus calories out – is over-simplified.
The other problem is that many foods that are selected on the basis of their calorie or fat content are not nutrient dense. Hence, they do not have significant quantities of micronutrients – vitamins and minerals. Of course, they will provide some vitamins and minerals but mostly what these foods provide is ‘empty calories’, calories that are devoid of or low in essential micronutrients, in the form of carbohydrates and not the good carbohydrates.
So food is more than calories – it provides nutrients – and the food’s nutrient density will determine how the body responds to it. So rather than focus on calories, we would do better for overall health (and weight) to focus on eating foods that are nutrient dense.
A substantial proportion of people do not adhere to weight loss interventions. Programmes supervising attendance, offering social support, and focusing on dietary modification have better adherence than interventions not supervising attendance, not offering social support, and focusing exclusively on exercise.8
The hormone leptin is designed to modulate a stable weight in individuals. It is one of the hormones released after a meal to make you feel full or satisfied and is produced by adipose tissue. Therefore, the more adipose tissue (or fat) you have the more leptin you produce, therefore the more satisfied you feel and the less you eat, reducing adipose tissue thereby maintaining a stable weight. However, many things can influence leptin signalling such as inflammation and high cortisol (stress). Also, hunger/satiety feedback mechanisms are ignored, i.e. you eat when you are not hungry, excess leptin is produced which can contribute to leptin resistance, this is a problem as then satiety feedback mechanisms do not work and hunger prevails, thereby increasing caloric intake, and adipose tissue and therefore leptin which is ineffective. Therefore, factors mentioned which impair leptin signalling need to be considered and attenuated in individuals.1,2
The body has other satiety mechanisms which can be useful to utilise to support healthy weight loss. Gastric stretch receptors detect the distension of the stomach wall in the presence of food, which directly stimulates neuronal pathways to the brain to trigger satiation and appetite reduction. Therefore low density foods which contain a high amount of fibre, will fill the stomach more readily and stimulate stretch receptors with a lower calorie intake. High fibre from vegetables with healthy fats and protein in a meal are a good combination for stimulating stretch receptors and release of satiety hormones and neuropeptides in response to food consumption.3
It should be noted that satiety mechanisms have always been thought to be solely reliant on macronutrient satiety (i.e. adequate protein, carbohydrates and fat). However, micronutrient levels are also essential for satiety. If cells are devoid of adequate micronutrients, the brain will signal the body to increase nutrient intake. Therefore, if food is not micronutrient dense the body will not feel adequately satisfied and will crave further nutrition. This can lead to an increase of caloric intake.
Bridge the nutrition gap
Nutrient intake is an important consideration in weight management. Although there is heavy focus on macronutrients micronutrient intake must also be considered. A typical westernised diet that is considered to contribute to obesity is devoid of many micronutrients due to heavy processing, reduced content in soil, and farming and transportation methods as well as food choices which are often high in calories but low in nutrients. Therefore, many people are considered to be over fed and under nourished. Inadequate vitamin and mineral intake is documented among individuals with obesity. Long-term weight loss maintenance in a widely used commercial programme was associated with a healthier diet pattern, including consuming foods with higher micronutrient density.
Many individuals who are overweight or obese exceed energy needs but do not meet vitamin and mineral requirements. Individuals with obesity are at risk for several micronutrient inadequacies, including inadequate iron, calcium, magnesium, zinc, copper, folate, and vitamins A, B12, C, D, and E. Poor diet quality, including limited fruits and vegetables, beans, and whole grains, and overconsumption of high-calorie, low nutrient value foods and added sugars are considered to be the major contributors to nutrient inadequacies.4
In the analysis of micronutrient intake from both diet and supplements, individuals who are able to maintain a healthy weight met the recommendations for the majority of micronutrients and were significantly more likely than weight stable individuals with obesity to meet the estimated average requirements for copper, magnesium, vitamin A, riboflavin, vitamin B6, and vitamin C.
Independent of the age group, the prevalence of vitamin D deficiency was 35% higher in obese subjects compared to the eutrophic group and 24% higher than in the overweight group.
Therefore, it is essential to consider nutrient status when working with weight loss clients, especially as it also plays an essential role in satiety.
Rebalance underlying conditions
This blog doesn’t have enough space to talk about this in explicit detail, as they would all be long articles in their own right. However, it is important to consider that obesity, weight gain or the inability to lose weight may be associated with other underlying conditions or imbalances. Certain pathologies within the body can lead to increased weight gain or as an inhibitor of weight loss. These include:
Excess inflammation; Inflammation and weight gain is a vicious cycle, as adipose tissue is a site of production of inflamamtory markers including CRP (C-Reactive Protein). As weight increases so does adipose tissue and therefore CRP and hence inflammation. The caveat of this is that inflammation inhibits weight loss via a number of mechanisms including increasing insulin resistance, interfering with leptin signalling (the effect is that the brain doesn’t get proper feedback, so leptin levels remain low which triggers appetite to increase and metabolism to slow (as if the body were starving) making weight loss pursuits even harder), and adrenal dysfunction.5
Adrenal dysfunction; High levels of stress have been shown to slow down metabolism (in a study, stressed women burned on average 104 calories fewer than non-stressed women). Prolonged stress leads to chronically elevated levels of cortisol, high cortisol is associated with elevated insulin (which stimulates fat storage) but also can interfere with appetite and stimulate sugar cravings. Individuals with elevated cortisol tend to gain abdominal fat. Adrenal support and stress management techniques may therefore be essential in supporting weight loss.6
Liver toxicity; the liver is an essential organ for both fat metabolism and insulin sensitivity. It is also the organ of detoxification and if these detoxification pathways become overwhelmed with dealing with products that need to be detoxified (e.g. processed foods, chemicals, environmental pollutants, alcohol and medications) then insulin sensitivity and fatty acid metabolism is affected reducing the ability to burn fat and increasing fat storage mechanisms. Visceral adiposity (fat around the middle) correlates with excess lipid accumulation in liver.7,8
Thyroid dysfunction; thyroid hormone is responsible for regulating metabolism, therefore if thyroid hormone production is low this can lead to a reduction in metabolic rate and hence, weight gain. However thyroid dysfunction is also associated with hyperinsulinemia, high levels of inflammation and cortisol and also leptin resistance. Therefore, thyroid dysfunction should be considered in weight loss patients.7,8
Oestrogen dominance; excess oestrogen is associated with weight gain, again via many mechanisms including affecting insulin signalling. Additionally, excess oestrogen is associated with both liver dysfunction and gut dysbiosis both of which are also independently associated with weight gain. Oestrogen is a growth promoting hormone and generally stimulated fat accumulation of the hips and breasts, so it is more associated with pear shaped weight gain rather than apple shaped. Although it can still influence the adrenal glands and therefore excess cortisol, so needs to be considered within the web of imbalances and physiology.7,8
Dysbiosis; Pivotal studies have demonstrated that manipulation of the gut microbiota and its metabolic pathways can affect host’s adiposity and metabolism. Converging evidence suggests a complex relationship between the gut microbiome, the host metabolic pathways, immune system, adipose tissue, genetic factors, and the host behaviours and diet. The tight interaction between diet, the gut microbiota and the host may be the basis of the ancient symbiotic relationship between the microbes and humans. Gut flora may directly affect weight but also elicits responses on the brain, thyroid, adrenals, oestrogen the liver and inflammation directly all of which influence appetite, weight gain and fat metabolism. Therefore, considering the health of the gut is essential in weight loss interventions.9
Exercise is undoubtedly excellent for health. It can assist weight loss as it increases calorie burning, maintains muscle mass (which is important for burning calories at rest and supporting insulin sensitivity). However, many people try to lose weight by just increasing exercise and research suggests this may be unhelpful as it can increase hunger and calorie intake. Also, excessive exercise without adequate recovery can increase inflammation and contribute to either weight gain or inhibiting weight loss. Exercise should be included along with healthy dietary alteration; it should be noted that exercise has multiple benefits to other aspects of health.
As a nutritional therapist I am not keen on the term diet as someone once said it is the word die with a “t” on the end! When I talk about dietary interventions I am referring to lifestyle changes which include changes to food intake if necessary to support health. However, the media portraits many dietary preferences which can be useful for weight loss. Any weight loss intervention should be considered a long-term change not a quick fix fad. Some interventions which have the most research behind them are described below:
Intermittent fasting or Time Restricted Feeding (TRE)
There are a few ways in which you can do intermittent fasting. The most popular ones are the 5:2 (fasting 2 days a week) or time restricted eating such as daily fasts 16:8 (fasting for 16 hours a day) 14:10 etc.
Studies have shown great support for these type of lifestyle interventions for supporting weight loos, however it can be difficult for some to maintain these in the long term10
One study showed that:
- 10 hr time-restricted eating (TRE) in metabolic syndrome (MetS) promotes weight loss
- TRE reduces waist circumference, percent body fat, and visceral fat
- TRE in MetS lowers blood pressure, atherogenic lipids, and glycated haemoglobin
Mediterranean Diet – The Mediterranean diet includes wholegrains, healthy fats from nuts, seeds, olive oil and fish as well as high fruit and vegetable intake. There is much research behind its benefits for cardiovascular health but also has been highlighted as useful for maintenance of healthy weight. Mediterranean diet may be a useful tool to reduce body weight, especially when the Mediterranean diet is energy-restricted, associated with physical activity, and more than 6 months in length. Mediterranean diet has not been shown to cause weight gain cause weight gain, which removes the objection to its relatively high fat content. These results may be useful for helping people to lose weight.11
Low fat diets – reducing fat has been used as a weight loss technique for a long time. However, since it gained popularity in the 1970s obesity has been on the rise. They really work as fat is more calorific gram for gram than carbs or protein, however fat plays and essential role in health. Also, healthy fats from olive oil, oily fish and avocados have been shown to support fat burning. Additionally, low fat diets can encourage the over consumption of carbohydrates, if these are refined (white carbs) or high in sugar this can actively contribute towards obesity. Therefore, in the long-term low-fat diets are not considered healthful. “Another problem is that, in general, obese individuals prefer highly processed foods containing simple sugars rather than complex/raw carbohydrates; thus a low fat diet could actually encourage the consumption of sugars and refined carbohydrates that can worsen weight problems and also facilitate dyslipidemia, especially in insulin resistance individuals.”
Low carbohydrate diets – as a consequence of the debatable efficacy of these types of diet, there has been increased interest in recent years in very low carbohydrate ketogenic diets (VLCKDs) or simply ketogenic diets (KDs). This involved removing all complex carbohydrates from grains. This has been shown to improve weight loss in obese individuals as well as an increased long-term weigh loss maintenance. The main problem with low carbohydrate diets is that they can be difficult to maintain, and it is important not to consume any carbohydrates at all as it will inhibit ketosis.12
- Although it is important not to consume excess calories in weight loss, calorie counting alone does not work as some low-calorie food as interfere with insulin signalling.
- Satiety mechanisms are important to stimulate the “full” feeling, therefore foods that are high in fibre and contain water, such as non-starchy vegetables are useful to include in every meal stimulate stretch receptors.
- It is important to consider underlying health conditions that may be inhibiting weight loss, including thyroid and adrenal dysfunction, oestrogen dominance, dysbiosis and liver toxicity.
- Most successful dietary interventions for weight loss are the Mediterranean diet (wholegrains, healthy fats from nuts, seeds, olive oil and fish as well as high fruit and vegetable intake) which may be best if grain intake is minimised, along with intermittent fasting or time restricted feeding (The most popular one are the 5:2 (fasting 2 days a week) or time restricted eating such as daily fasts 16:8 (fasting for 16 hours a day) 14:10 etc.)
- Exercise is essential for all aspects of health and wellbeing, but it is important that exercising with weight loss should be done alongside dietary alterations as well as in some cases it may encourage weight gain.
- Micronutrient intake is essential for satiety, and obesity is associated with sub-optimal levels of micronutrients. Therefore, a multivitamin and mineral may be useful for weight loss.
If you have questions regarding the topics that have been raised, or any other health matters, please do contact me (Helen) by phone or email at any time.
Amanda Williams and the Cytoplan Editorial Team
- Zhang Y, Chua S Jr. Leptin Function and Regulation. Compr Physiol. 2017 Dec 12;8(1):351-369.
- Crujeiras AB, Carreira MC, Cabia B, Andrade S, Amil M, Casanueva FF. Leptin resistance in obesity: An epigenetic landscape. Life Sci. 2015 Nov 1;140:57-63.
- Amin T, Mercer JG. Hunger and Satiety Mechanisms and Their Potential Exploitation in the Regulation of Food Intake. Curr Obes Rep. 2016 Mar;5(1):106-12. doi: 10.1007/s13679-015-0184-5
- Pascual RW, Phelan S, La Frano MR, Pilolla KD, Griffiths Z, Foster GD. Diet Quality and Micronutrient Intake among Long-Term Weight Loss Maintainers. Nutrients. 2019;11(12):3046.
- Hardy OT, Czech MP, Corvera S. What causes the insulin resistance underlying obesity?. Curr Opin Endocrinol Diabetes Obes. 2012;19(2):81-87. doi:10.1097/MED.0b013e3283514e13
- Kiecolt-Glaser JK, Habash DL, Fagundes CP, et al. Daily stressors, past depression, and metabolic responses to high-fat meals: a novel path to obesity. Biol Psychiatry. 2015;77(7):653-660. doi:10.1016/j.biopsych.2014.05.018
- Murray, JPM (2013) Textbook of Natural Medicine. 4th Ed.
- Bland J et al. Textbook of Functional Medicine.; 2008.
- Sanmiguel C, Gupta A, Mayer EA. Gut Microbiome and Obesity: A Plausible Explanation for Obesity. Curr Obes Rep. 2015;4(2):250-261.
- Esposito K, Kastorini CM, Panagiotakos DB, Giugliano D. Mediterranean diet and weight loss: meta-analysis of randomized controlled trials. Metab Syndr Relat Disord. 2011;9(1):1-12. doi:10.1089/met.2010.0031
- Bueno, N., De Melo, I., De Oliveira, S., & Da Rocha Ataide, T. (2013). Very-low-carbohydrate ketogenic diet v. low-fat diet for long-term weight loss: A meta-analysis of randomised controlled trials. British Journal of Nutrition, 110(7), 1178-1187.
- Lemstra M, Bird Y, Nwankwo C, Rogers M, Moraros J. Weight loss intervention adherence and factors promoting adherence: a meta-analysis. Patient Prefer Adherence. 2016;10:1547-1559. Published 2016 Aug 12.