Popular Diets

Wendy Dahl, PhD Associate Professor and Extension Specialist UF/IFAS Food Science & Human Nutrition Dept. [email protected]

1 Webinar Team

Wendy Dahl, Ph.D. Julie England, M.S.,CFCS Associate Professor and Extension Specialist Seminole County FCS & Food Wendy Wood Lynch, M.S. UF/IFAS Food Science & Human Nutrition Depart. Systems Extension Agent Putnam County FCS Extension Agent [email protected] [email protected] [email protected]

2 Saturday Evening Post September 22nd 1934

• Walking is becoming a lost art! - one car for every 5 people!  • Perpendicular diet – limiting to one, two or a few foods • Horizontal diet – a variety of foods – but less • A 18-day Hollywood Diet ‘What day are you on?’

3 4 It’s not just about weight loss, but also perceived health benefits.

Are we destined to repeat history?

5 Health effects of dietary risks in 195 countries, 1990–2017: a systematic analysis for the Global Burden of Disease Study 2017

www.thelancet.com Published online April 3, 2019 http://dx.doi.org/10.1016/S0140-6736(19)30041-8 6 Mediterranean Dietary Pattern Associated with decreased chronic disease risk:  Olive oil ↓ Cardiovascular disease (Grosso et al. 2015)  Fruit ↓ High blood pressure (Nissensohn et al. 2016)  ↓ Metabolic syndrome (Godos et al. 2017) Vegetables ↓ Cancers (Schwingshackl & Hoffman 2015)  Whole grains ↓ Type 2 Diabetes (Jannasch et al. 2017)  Nuts and seeds ↓ Cognition (Solfrizzi et al. 2017)  Legumes/pulses Some evidence for lower central obesity  Fish and lean meats (Bendall et al. 2018) but weight loss requires eating less  Limiting red meat, butter, *Also effective for managing chronic disease sweetened beverages, e.g. diabetes sweets pastries, etc.

7 Raw Foods Diet: What do the proponents say?

• Claims for improving health, preventing development of chronic disease, and promoting weight loss. • Claims that cooking foods above 118° F will destroy beneficial enzymes and nutrients. • Recommended preparation methods include juicing, blending, dehydrating, sprouting, cutting, chopping, and slicing.

J Nutr. 2005;135(10):2372-2378.

8 Raw Foods Diet: What foods are allowed?

• Raw fruits and vegetables • Raw seeds and nuts • Unpasteurized milk • Sprouted grains and beans • Cold-pressed extra-virgin olive oil • Raw virgin coconut oil • Raw fish, raw eggs and raw meats

9 Raw Foods Diet: What does the science say?

• Health benefits associated with • Decreased digestibility will lead to less consuming fruits and vegetables (but provision of calories, protein and also including cooked) other nutrients and possible weight • A host of human enzymes for optimal loss and malnutrition. digestion – enzymes in raw foods not needed • Yes, some of vitamins are destroyed with cooking but cooking also improves digestibility (e.g. protein) and bioavailability (e.g. lycopene in tomato sauce)

10 Raw Foods Diet: What are the pros and cons?

Pros Cons • Promotes high intake of fruits • High risk of foodborne illness and vegetables with raw meat, eggs, fish and • High in fiber milk but also with sprouting • Includes minimally processed • Anti-nutrients in some raw foods foods (e.g. legumes) • May be lower in calories • Restrictive, lots of preparation • Undernutrition is possible

11 Alkaline Diet: What do the proponents say?

• Eating foods such as meat, dairy and refined foods produce acids leading to disease

• Eating fruits and certain vegetables alkalizes the body

• Hydration is critical – expensive alkaline water needed

12 Alkaline Diet: What does the science say?

• To stay in acid-base balance, we need healthy kidneys and healthy lungs • In health, we can’t and shouldn’t try to change the body pH • Fruits and vegetables are health enhancing for a variety of reasons. • In the extreme - overall very poor quality diet lacking in fruits and vegetables and lots of excess protein, there may be imbalance (Institute of Medicine 2004)

13 Normal serum pH 7.35-7.45 Acid-base Balance

Respiratory regulatory Kidney [metabolic] control regulatory control

• Change in respiration • Control of rate bicarbonate • Depth of breathing • Phosphate, sulfate • Release or retention of and ammonium buffers CO2 J Environ Public Health 2012; doi: 10.1155/2012/727630 16 What can go wrong with acid-base balance?

• Respiratory Acidosis • Respiratory Alkalosis – Hypoventilation (↓ breathing) – Hyperventilation (rapid leads to retention of CO2 and ↑ breathing) leads to loss of CO2 acid • Metabolic Acidosis • Metabolic Alkalosis – Loss of bicarbonate or excess – Vomiting production of acid (e.g. chronic kidney disease, diabetic – Low blood potassium ketoacidosis, lactic acidosis) – Excessive use of antacids (i.e. – Diarrhea – most common cause calcium carbonate)

Diet alone does not cause acidosis or alkalosis – except in extremes and in high risk individuals.

17 Alkaline Diet: Pros and Cons

Pros Cons • Increased fruit and vegetable • Exclusion of so-called “acidic” intake foods may lead to nutrient inadequacies (protein, iron, calcium etc.) • Very high intakes of oxalate- containing vegetables (e.g. spinach) may be risky for some individuals.

J Ren Nutr 2018 May;28(3):215-220. 18 Paleo Diet: What do the proponents say?

• Claim that we need to eat as human hunters and gatherers might have eaten during the Paleolithic era > 10,000 years ago before the introduction of agriculture. • Claim our bodies are mismatched with the modern diet. • Promoted for weight management and overall health.

19 Paleo Diet: What foods are allowed?

Allowed Not allowed • Lean meats (grass fed) • Cereal grains • Fish/seafood • Legumes • Fresh vegetables and fruit • Dairy • Nuts and Seeds • Potatoes • Eggs • Refined oils, processed • Healthful oils foods, refined sugar and salt

20 Paleo Diet: What does the science say?

• Evidence that the Paleolithic diet has favorable effects on cardiovascular disease risk factors: weight status, lipid profile, blood pressure, and inflammatory markers.

• “…the evidence is not conclusive and more well-designed trials are still needed.”

Adv Nutr. 2019 Apr 30. pii: nmz007. doi: 10.1093/advances/nmz007

21 Paleo Diet: Pros and Cons

Pros Cons Depending on food choice… • No dairy (calcium, vitamin D) • Higher fiber • No whole grains and health • Low sodium benefits • Higher antioxidants • Long-term effects? • Cost and sustainability

22 Ketogenic Diet: What do the proponents say?

• Claims related to weight loss, diabetes, polycystic ovary syndrome, acne, neurological diseases, cancer and decreased respiratory and cardiovascular disease risk factors. • All due to shifting the energy source from glucose to ketone…

European Journal of Clinical Nutrition (2013) 67, 789–796

23 Ketogenic Diet: What foods are allowed?

Very high fat, very low carbohydrate, and moderate protein. • Oils, butter, mayonnaise, and cream • Cheese, nuts, meats, poultry, fish, shellfish, eggs • Green leafy vegetables

Foods with higher amounts of carbohydrates such as grains, fruit, root vegetables, and legumes are restricted.

A meal of heavy whipping cream, mayonnaise, meat, a green vegetable, dill pickle, and MCT oil – how does that sound?

24 Ketogenic Diet: What does the science say?

• Glucose from carbohydrate-containing foods and stored glucose is normally used for energy • During starvation or on a diet with very low carbohydrate, ketones are produced from fat for fuel in 3-4 days or so – state of ‘ketosis’. • Evidence for the treatment of intractable epilepsy – speculative/no strong evidence for other neurological diseases. • Chronic disease management? Risk factors vs. disease risk e.g. blood glucose

European Journal of Clinical Nutrition (2013) 67, 789–796

25 Ketogenic Diet: Pros and Cons

Pros Cons • May be metabolic changes that • Very unpalatable diet help to promote weight loss and • Unknown long-term risks improvements in certain health • Low in fiber – ↑ health risks indicators in the short term. • Low in certain nutrients – deficiencies possible • Fatigue, poor mood, constipation and other reported side effects

European Journal of Clinical Nutrition (2013) 67, 789–796

26 FODMAPS Diet: What do the proponents say?

• FODMAPS = Fermentable, Oligo, Di- Monosaccharides and Polyols • Claims that undigested sugars lead to diarrhea and gastrointestinal symptoms • Recommend an elimination diet and reintroduction while monitoring symptoms

*These fermentable carbohydrates naturally found in foods are prebiotic! Enhance beneficial bacteria.

27 FODMAPS Diet: What foods are restricted?

• Vegetables: onions, garlic, asparagus, mushrooms, green peas • Pit fruits (e.g. cherries), apples, pears, watermelon • Dairy with lactose • Protein: Legumes, some processed meats • High fructose corn syrup, honey, sugar alcohols. • Grains: wheat/rye/barley (fructans)

https://www.monashfodmap.com/about-fodmap-and-ibs/high-and-low-fodmap-foods/ 28 FODMAPS Diet: What does the science say?

Fiber and Resistant Starch Proteins, peptides & Oligosaccharides & sugars (FODMAPS) amino acids

Microbiota - Fermentation

More bacteria Short chain Gases Other products fatty acids FODMAPS Diet: What are the pros and cons?

Pros Cons • Not meant for weight loss – no • Possible nutrient inadequacies evidence to date • Promotes disordered eating? • Reduced distension/bloating and • Unfavorable gut microbiota – therefore less symptoms in health effects unknown people with irritable bowel syndrome

30 Gluten Free: What do the proponents say?

• Prescribed for individuals with celiac disease and increasingly for non-celiac gluten sensitivity

• Some are promoting the diet X for weight loss or just an overall “healthier diet”

31 Gluten Free: What foods are allowed?

• All foods except those containing gluten (a protein fraction) found in wheat, barley and rye – even trace amounts • Other grains (e.g. oats) are allowed if grown/transported/processed to ensure very low contamination with gluten.

32 Gluten Free: What does the science say?

• Celiac disease – an autoimmune disorder affecting digestion – exposure to gluten leads to profound damage to the intestinal villi affecting nutrient absorption. • Gluten free diet required to manage celiac disease - therapeutic when diet is strict and lifelong. • Non-Celiac Gluten Sensitivity - less defined syndrome and “prevalence of NCGS after gluten re-challenge is low, and the percentage of relapse after a gluten or a placebo challenge is similar” NCGS overlap with IBS.

Front Physiol 2017 Sep 5;8:621. doi: 10.3389/fphys.2017.00621.

33 Gluten Free: What are the pros and cons?

Pros Cons (for those not requiring it) • Therapeutic for celiac disease • Gluten free products may be when diet is strict and lifelong. lower in fiber and certain nutrients specific to enriched grains e.g. folic acid, iron, niacin, riboflavin and thiamin • May contain more added fat and sugars • More expensive – more time – less fun

34 Conclusions

• There is no magic fad diet…after almost 100 yr of research. • Overwhelming evidence for benefits of whole grains, fruits, vegetables, and other plant foods – beware of diets that exclude these foods. • Moderate intake of animal-sourced foods in a plant-based diet supports good health as do well planned vegetarian diets – beware of diets that promote high intakes of animal-sourced foods and fat vs. fiber • Especially beware of “perpendicular” (one food wonder) diets

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